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http://www.archive.org/details/heartrhythmsOOIams 


To  A.  D. 


I 


i 


THE 

Heart  Rhythms 


PAUL  DUDLEY  LAMSON,  M.D. 

Associate  Professor  of  Pharmacology 
Johns  Hopkins  University 


BALTIMORE 

WILLIAMS  AND  WILKINS  COMPANY 

1921 


dT-         S- 


I  -y  —!     O  f  ^ 


Copyright  1921 
WILLIAMS  &  WILKINS  COMPANY 

Made  in  United  States  of  America 

All  rights  reserved,  including  that  of  translation 

into  foreign  langtiages,  including 

the  Scandinavian. 


COMPOSED  AND  PRINTED  AT  THE 

WAVERLY  PRESS 

By  THE  Williams  &  Wilkins  Company 

Baltimore,  Md.,  U.  S.  A. 


CONTENTS 

Introduction 7 

PART  I 
Chapter  I 

THE  DEVELOPMENT  OF  OUR  KXOWT-EDGE  OF  THE  HEART  RHYTHMS 

The  pulse   I3 

The  sphygmograph 14 

The  polygraph 16 

The  electrocardiograph I9 

Ch.^ter  II 

FIVE  DIPORTAXT  ELEMENTS   OF  THE  HEART  BEAT 

1.  The  simultaneous  contraction  of  both  auricles  and  both  ventricles 24 

2.  The  rhythroicity  of  beat  of  cardiac  muscle 26 

3.  The  impulse  for  contraction  occurs  at  the  point  of  greatest  irritability. . .  26 

4.  The  refractory  period  of  the  ventricles 27 

5.  The  conduction  of  impulses  from  auricle  to  ventricle 27 

Summary 29 

Chapter  III 

THE  DIVISION  OF   THE  HEART  INTO  FUNCTIONAL  AREAS   BY  MEANS   OF  THE 
ELECTROCARDIOGRAPH 

1.  The  sino-auricular  node 32 

2.  The  auricular- ventricular  node  and  bundle 33 

3.  The  auricular  musculature 33 

4.  The  ventricular  musculature 33 

Chapter  IV 

THE  CLASSIFICATION  OF   THE  HEART  RHYTHMS   ON  THE  BASIS   OF  POINT   OF 
ORIGIN   OF  lilPULSES 

I.  Sino-auricular  rhythms 35 

1.  The  normal  heart  beat 36 

a.  Simple  tachycardia 36 

b.  Simple  bradycardia 36 

c.  Sinus  arrhythmia 37 

2.  Ectopic  beats  interrupting  the  normal  heart  beat 37 

a.  Ectopic  auricular  beats 3/ 

b.  Ectopic  auricular  ventricular  nodal  beats 39 

c.  Ectopic  ventricular  beats 40 

II.  Ectopic  auricular  rhythms 41 

1.  Paroxysmal  tachycardia 42 

2.  Auricular  flutter 43 

3.  Auricular  fibrillation 45 

5 


6  CONTENTS 

in.  Auricular  ventricular  nodal  rhythms 48 

rV.  Ectopic  ventricular  rhythms 49 

Summary  of  ectopic  rhythms 51 

Chapter  V 

ABNORMALITIES   OF   CONDUCTION  FROM  AURICLE  TO  VENTRICLE 

1.  Increased  conduction  time 52 

2.  Dropped  beats  or  partial  block 52 

3.  Complete  block  or  idio-ventricular  rhythm 52 

PART  II 
Chapter  I 

INTERPRETATION  OF  THE  ELECTROCARDIOGRAM 

Chapter  II 

THE  POLYGRAPH,   SPHYGMOGRAPH,  AND  PULSE 

Instruments 64 

The  radial  pulse 69 

The  venous  pulse 72 

Chapter  III 

POLYGRAPHIC  CURVES 

I.  Sino-auricular  rhythms 83 

a.  The  normal  heart  beat 83 

b.  Simple  tachycardia 83 

c.  Simple  bradycardia 83 

d.  Sinus  arrhythmia 83 

II.  Ectopic  beats  interrupting  normal  rhythms 85 

a.  Ectopic  auricular  beats 85 

b.  Ectopic  auricular- ventricular  nodal  beats 85 

c.  Ectopic  ventricular  beats 86 

m.  Ectopic  auricular  rhythms 87 

a.  Paroxysmal  tachycardia 87 

b.  Auricular  flutter 87 

c.  Auricular  fibrillation 89 

IV.  Auricular-ventricular  nodal  rhythms 89 

V.  Ectopic  ventricular  rhythms 91 

VI.  Abnormalities  of  conduction  from  auricle  to  ventricle 91 

a.  Prolonged  conduction  time 91 

b.  Dropped  beats  or  partial  block 91 

c.  Complete  block  or  idio-ventricular  rhythm 93 

Summary  of  polygraphic  tracings 93 

Summary  of  sphygmographic  tracings 95 

Construction  of  diagrammatic  curves 96 


INTRODUCTION 

The  object  of  this  book  is  not  to  present  anything  new  in 
regard  to  the  cardiac  rhythms,  but  to  separate  them  from 
the  intricate  mass  of  information  concerning  instruments, 
curves,  cardiac  physiolog>%  etc.,  in  which  they  are  often 
buried,  and  to  consider  the  rhythms  themselves  as  a  whole, 
and  in  relation  to  each  other,  but  apart  from  all  other  func- 
tions of  the  heart.  In  doing  so  they  stand  out  as  a  very 
simple  and  definite  mechanism,  which  when  once  understood 
can  never  be  forgotten. 

The  general  plan  of  this  book  was  developed  in  1912 
after  studying  in  London,  was  used  in  the  next  year  in 
teaching  at  the  Peter  Bent  Brigham  Hospital,  Boston, 
and  since  then  in  connection  with  lectures  in  pharmacology 
at  Johns  Hopkins  University.  On  account  of  various  re- 
quests during  the  past  ten  years  to  publish  this  plan  of  the 
heart  rhythms  the  book  has  finally  been  completed. 

The  lack  of  a  clear  understanding  of  the  rhythms  of  the 
heart  among  well  informed  clinicians  and  students  is  quite 
surprising  but  easily  accounted  for.  The  subject  is  of 
fairly  recent  development,  only  a  \-ery  meager  knowledge 
being  had  before  the  advent  of  the  electrocardiograph  in 
about  1910.  Up  to  this  time  the  polygraph  was  used  by 
a  few  people  and  it  was  possible  for  even  the  most  experienced 
to  interpret  only  a  part  of  their  curves,  and  the  whole  sub- 
ject was  entirely  out  of  reach  of  the  busy  practitioner.  The 
electrocardiograph  cleared  up  the  heart  rhythms  at  once. 
It  is  this  fact  which  has  been  generally  overlooked,  and  which 
makes  such  a  book  as  this  possible.  The  subject  of  heart 
physiology  is  of  course  in  its  infancy,  as  is  the  cause  of  the 

7 


8  INTRODUCTION 

heart  beat,  etc.,  but  the  rhythms  of  the  heart  as  such  are 
simply  the  time  relations  of  contractions  of  auricles  and 
ventricles  and  these  have  been  satisfactorily  worked  out. 

It  is  now  possible  to  present  a  diagrammatic  scheme  of  the 
heart  divided  into  four  areas  from  which  impulses  for  con- 
traction can  arise.  As  these  areas  comprise  the  entire 
heart,  no  other  points  of  origin  of  impulses  can  exist.  A 
scheme  of  heart  rhythms  on  the  basis  of  point  of  origin  of 
impulses  can  then  be  worked  out  which  must  include  all 
rhythms.  Given  a  few  (five)  functions  of  cardiac  muscle, 
rhythms  may  be  calculated  by  a  mathematician  with  no 
other  knowledge  of  the  heart.  There  will  be  a  limited 
number  of  rhythms,  and  each  of  them  has  been  found  to 
occur  chnically.  With  such  a  scheme  it  is  impossible  to 
forget  the  rhythms  as  they  can  always  be  worked  out.  Any 
curve  or  tracing  obtained  from  a  patient  can  be  referred  to 
this  process  of  analysis,  and  can  be  classified  at  once. 
Finally  one  has  a  clear  mental  picture  of  the  limits  of  cardiac 
rhythms  and  will  not  waste  time  over  each  new  curve 
imagining  that  he  has  some  totally  new  rhythm. 

The  clinical  value  of  a  knowledge  of  these  rhythms  is 
of  far  greater  importance  than  those  not  understanding  the 
rhythms  reahze.  The  actual  diagnosis  cannot  be  made  with- 
out the  use  of  an  instrument,  in  many  cases  by  the  electro- 
cardiograph only,  which  is  a  cumbersome,  expensive  and 
complicated  instrument  quite  out  of  reach  from  a  financial 
point  of  view  of  the  general  practitioner,  but  which  should 
be  part  of  the  equipment  of  every  hospital.  The  polygraph, 
a  small  portable  instrument,  can  however  be  used  by  anyone, 
and  should  come  into  more  general  use.  It  is  of  absolutely 
no  value  -without  a  complete  knowledge  of  the  cardiac 
rhythms.  The  reason  for  this  is  that  the  polygraph  gives 
no  characteristic  curves  for  the  auricle  and  an  interpreta- 


INTRODUCTION  9 

tion  can  be  made  only  by  careful  plotting  of  time  relations, 
while  in  the  electrocardiogram  the  auricular  and  ventricular 
impulses  are  shown  by  complexes  of  characteristic  shape 
and  can  be  recognized  at  once.  Besides  this  in  many  cases 
only  incomplete  information  can  be  obtained  by  a  poly- 
graphic  tracing  and  a  diagnosis  made  by  exclusion  only, 
which  is  impossible  when  the  limit  of  rhythms  is  not  defi- 
nitely known.  The  instrument  is  much  harder  to  use  in- 
telhgently  than  the  larger  electrocardiograph  and  the  cup- 
boards of  many  a  practitioner  probably  hold  one  of  these 
discarded  machines.  An  intelUgent  understanding  of  the 
rhythms  themselves  apart  from  other  heart  functions, 
instruments,  and  curves,  gives  one  a  basis  on  which  to  reason 
out  a  case,  and  will  allow  every  practitioner  to  treat  his 
patients  more  intelligently  whether  the  diagnosis  is  made 
from  feehng  the  pulse,  taking  a  sphygmographic  or  poly- 
graphic  tracing,  or  an  electrocardiogram. 

The  book  is  divided  into  two  parts.  It  is  hoped  that 
the  first  will  be  found  readable,  and  from  it  one  can  obtain 
an  intelligent  understanding  of  the  heart  rhythms.  In  the 
second  part  a  very  brief  outline  of  the  electrocardiograph 
and  the  taking  of  electrocardiograms  is  given.  It  is 
assumed  that  anyone  using  such  an  instrument  would 
require  a  much  more  detailed  knowledge  than  the  scope 
of  this  book  allows. 

The  polygraph  however  is  taken  up  at  length.  With  a 
clear  understanding  of  the  heart  rhythms,  this  instrument 
is  of  great  clinical  importance,  and  is  well  worth  a  careful 
study.  Its  use  requires  care,  and  as  ma,ny  curves  can  be 
diagnosed  by  exclusion  only  it  is  essential  to  have  a 
knowledge  of  all  the  rhythms  before  a  diagnosis  can  be 
made.  Although  this  requires  considerable  careful  study 
it  is  hoped   that  the  pointing  out  of  the  few  essential 


10  INTRODUCTION 

factors  necessary  for  the  taking  of  a  curve,  here  given,  will 
simplify  this  apparently  complex  subject. 

References,  names  of  authors  and  investigators,  have 
been  left  out  to  avoid  confusion.  The  book  is  written 
with  the  purpose  of  arranging  the  great  mass  of  informa- 
tion which  has  grown  out  of  years  of  work  by  many  in- 
vestigators; and  presenting  it  in  as  concise  a  form  as 
possible  in  order  that  it  may  be  more  widely  used  in  the 
study  and  treatment  of  those  suffering  from  disorders  of 
the  heart.  The  student  or  reader  who  wishes  to  go 
further  will  find  each  phase  discussed  in  detail  in  many 
excellent  books  on  the  subject. 

I  wish  here  to  express  my  thanks  to  the  Arthur  H. 
Thomas  Co.  and  The  Cambridge  and  Paul  Instrument 
Company,  Limited,  for  their  courtesy  in  allowing  me  to 
use  cuts  of  their  instruments. 

P.  D.  L. 

Baltimore,  August  1,  1921. 


PART  I 


CHAPTER  I 

The  De\^lopment  of  Our  Knowledge  of  the  Heart 

Rhythms 

the  pulse 

Probably  the  first  interest  in  heart  rhythms  came  from 
"taking  the  pulse."  This  usually  meant  feeling  the  pulse 
wave  in  the  radial  artery  at  the  wrist,  and  we  find  very 
early  records  of  fast,  slow,  and  irregular  pulses,  but  these 
were  taken  as  signs  of  the  patient's  condition  and  little  atten- 
tion was  paid  to  the  reason  for  and  the  mechanism  of  their 
production.  The  pulse  was  easily  felt  and  gave  the  physi- 
cian perhaps  as  much  information  as  any  single  examination 
does.  B}'  it  he  was  able  to  tell  whether  the  heart  were 
beating  regularly  or  irregularly,  fast  or  slowly,  whether 
each  beat  were  large  and  forcible,  or  small  and  weak,  and 
whether  beating  against  the  normal,  high  or  low  pressure. 
It  was  an  important  examination,  but  did  not  explain  the 
cause  of  these  different  rhvthms.  If  we  represent  the 
circulation  as  in  figure  1  it  will  be  seen  that  the  radial  pulse, 
or  any  other  arterial  pulse,  is  a  direct  index  of  left  ven- 
tricular contraction  only,  as  this  is  the  one  heart  chamber 
pumping  blood  into  the  aorta,  the  right  auricle  emptying 
into  the  right  ventricle,  the  right  ventricle  into  the  lungs, 
and  the  left  auricle  into  the  left  ventricle.  A  study  of  the 
pulse  alone  gives  then  no  idea  of  what  the  auricles  are  doing, 
but,  as  we  shall  see  later,  when  the  relationship  between 
ventricular  and  auricular  contraction  is  once  understood, 
it  is  possible  to  infer  by  feeling  the  pulse  what  is  going  on 
in  the  auricles,  so  that  a  knowledge  of  the  i:)ulse  is  at  present 
even  more  valuable  than  before. 

13 


14 


THE  HEART  RHYTHMS 
THE  SPHYGMOGRAPH 


The  first  careful  study  of  the  pulse  was  made  by  using 
an  instrument  called  the  "  sphygmograph, "  with  which  the 
pulse  waves  could  be  recorded  (see  fig.  2).  This  was  done 
by  placing  a  tambour  with  a  rubber  membrane,  in  the  center 
of  which  was  a  button,  on  the  wrist  in  such  a  manner  that 
the  button  pressed  on  the  radial  artery.     This  tambour 


/\oria  and  Adenal  Pukes, 

Fig.  1.  Diagrammatic  representation  of  the  heart  showing  that  the  arterial 
pulse  is  an  index  of  left  ventricular  contraction  only. 

was  connected  by  a  rubber  tube  with  a  second  tambour, 
to  which  a  lever  recording  on  a  smoked  drum  was  attached. 
Each  pulse  wave  compressed  the  air  in  the  tambour,  and 
transmitted  this  wave  to  the  lever,  which  recorded  the  pulse 
in  a  continuous  curve.  The  time  was  also  recorded,  usually 
in  one-fifth  second  intervals.  Such  a  sphygmographic 
curve  is  shown  diagrammatically  in  figure  3.  With  this 
instrument  the  time  of  left  ventricular  contraction  could 


DEVELOPMENT  OF  KNOWLEDGE  OF  HEART  RHYTHMS    15 

be  recorded  very  accurately.  The  shape  of  the  curve  had 
Httle  significance  as  it  depended  on  the  instrument  used, 
and  its  adjustment  to  the  UTist,  but  two  points  in  the  curve 


Fig.  2.  Showing  the  principle  of  the  sphygmograph.  The  tambour  placed 
over  the  radial  artery  transmits  an  air  wave  to  the  tambour  and  recording  lever 
which  records  the  pulse  wave  on  the  revolving  drum.  A  time  marker  is  shown 
which  is  essential  for  the  interpretation  of  these  curves. 

were  found  to  be  of  great  importance:  the  first  of  these 
(1)  the  beginning  of  the  upstroke,  being  an  index  of  the 
beginning  of  left  ventricular  contraction,  and  the  "dicrotic 
notch"  (J)|(a!^discussion  of  which  will  be  found  on  page 


16 


THE  HEART  RHYTHMS 


(69)  marking  the  end  of  contraction.  The  end  of  the 
upstroke  {2)  has  no  significance,  as  it  depends  upon  the 
inertia  of  the  lever.  If  a  hght  dehcate  instrument  is  used, 
the  lever  will  follow  approximately  the  true  pulse  curve, 
while  if  it  is  heavy  it  will  fly  up,  making  a  sharp  peak  which 
is  very  different  from  the  true  curve. 

The  sphygmograph  was  an  advance  over  simply  feeling 
the  pulse  but  it  gave  us  an  index  of  left  ventricular  contrac- 
tion only. 


Fig.  3.  A  diagrammatic  representation  of  various  forms  of  sphygmographic 
tracings.  The  beginning  of  systole  (1),  and  tlie  dicrotic  notch  {3),  the  end  of 
systole  are  the  only  points  of  importance.  The  points  {2)  and  {4)  are  variables 
depending  on  the  instrument  used,  conditions  of  blood  pressure,  etc.,  and  may 
be  entirely  disregarded. 

THE  POLYGRAPH 

A  great  advance  over  the  sphygmograph  was  made  by 
simultaneously  recording  the  radial  pulse,  the  venous  pulse 
in  the  neck,  and  the  time,  with  an  instrument  called  the 
"polygraph. "  This  apparatus  recorded  the  pulse  in  exactly 
the  same  manner  as  the  sphygmograph,  while  a  second 
similar  recording  device,  placed  over  the  right  jugular  vein, 
recorded  the  pulse  waves  in  this  vessel.  In  a  normal  case 
under  good  conditions,  curves  similar  to  those  in  figure  4 
were  obtained.  The  beginning  of  left  ventricular  systole 
is  shown  in  the  radial  pulse  curve,  and  by  a  correspond- 
ing wave  c  in  the  venous  curve,  the  end  of  systole  by  the 


DEVELOPMENT   OF   KNOWLEDGE   OF   HEART   RHYTHMS         17 

dicrotic  notch  in  the  radial  curve,  and  the  downstroke 
V  in  the  venous  cur\-e.  One  other  wave  (a)  is  seen  in 
the  venous  tracing,  which  occurs  one-fifth  of  a  second 
before  each  ventricular  systole.  This  was  found  to  be  due 
to  contraction  of  the  auricles,  so  that  with  this  instrument 


Fig.  4.  The  upper  curve  is  an  actual  polygraphic  tracing.  The  lower  one  a 
diagrammatic  representation  of  one.  It  is  seen  that  while  the  sphygmographic 
tracing  shows  ventricular  beats  only,  the  venous  tracing  shows  auricular  as  well 
as  ventricular  beats.  The  points  (a)  showing  auricular  contraction,  and  the 
points  (c)  and  (v)  showing  the  beginning  and  end  of  ventricular  systole. 

it  is  possible  to  record  auricular  as  well  as  ventricular 
beats.  But  difficulties  were  encountered  which  made  this 
apparatus  less  simple  than  it  appeared  to  be.  In  some  cases 
where  the  patient  moved  or  coughed,  other  waves  appeared 
in  the  venous  curve  as  shown  in  figure  5  and  in  still  other 


18 


THE  HEART  RHYTHMS 


cases  as  in  figure  6  no  auricular  waves  appeared  at  all. 
It  soon  became  evident  that  the  venous  pulse  gave  a  very 
uncertain  curve.  Taken  by  itself  the  curve  has  no  charac- 
teristic waves  as  the  radial  curve  has.  It  is  then  of  no 
value  alone  but  only  when  taken  in  relation  to  a  curve  in 
which  definite  points  are  known,  as  the  radial  curve.  It 
is  possible  to  plot  the  beginning  and  end  of  systole,  definitely 


Time  /t  " 

Fig.  5.  This  curve  is  given  to  show  that  the  interpretation  of  polygraphic 
curves  is  not  simple.  Besides  the  auricular  and  ventricular  waves  other  waves 
may  occur  from  movements  of  the  patient  or  the  instrument,  and  these  can  be 
told  from  the  auricular  and  ventricular  waves  only  by  careful  plotting  of  known 
points  in  the  curve. 


Fig.  6.  In  this  polygraphic  curve  no  auricular  waves  appear  at  all,  in  which  case 
one  is  not  certain  whether  the  auricle  is  beating  or  whether  the  curve  is  simply 
badly  taken. 

shown  in  the  radial  curve,  onto  the  venous  curve,  marking 
where  the  beginning  and  end  of  systole  come  in  this  curve. 
In  this  manner  the  waves  which  are  of  ventricular  origin 
are  found,  and  we  can  look  about  for  other  waves  which 
might  be  caused  by  contraction  of  the  auricles.  In  some 
cases  these  waves  are  very  clear,  in  others  absent  or  obscure, 
and  though  by  careful  study  a  great  advance  was  made  in 


DEVELOPMENT   OF   KNOWLEDGE   OF  HEART  RHYTHMS         19 

our  knowledge  of  pathological  rhythms  by  the  use  of  this 
instrument  the  whole  subject  was  uncertain,  and  too  difficult 
for  anyone  but  an  expert. 

THE  ELECTROCARDIOGRAPH 

The  instruments  of  which  we  have  thus  far  spoken  re- 
corded mechanically  the  pulse  waves  which  follow  heart 
beats.  In  the  electrocardiograph  we  have  an  instrument 
of  an  entirely  different  character,  which  has  nothing  to  do 
with  the  actual  contraction  of  the  heart,  but  records  the 
impulses  for  these  contractions.  The  principle  is  a  simple 
one  although  the  instrument  is  of  formidable  appearance. 
It  is  based  on  the  fact  that  for  a  muscle  to  contract  a  stimu- 
lus is  necessary,  and  when  this  stimulus  arises,  whether  it 
be  of  nervous,  mechanical,  or  chemical  nature,  an  electrical 
difiference  of  potential  is  set  up  in  the  muscle  just  before 
its  contraction.  It  is  unnecessary  here  to  go  into  the  theory 
of  this  electrical  disturbance,  the  important  point  being 
that  it  takes  place  a  fraction  of  a  second  before,  rather  than 
as  the  result  of  contraction,  and  we  speak  of  it  as  an  "im- 
pulse" for  contraction.  Such  a  distrubance  occurs  when 
any  muscle  contracts,  and  as  the  heart  is  a  large  muscle 
it  causes  a  relatively  large  disturbance.  These  changes  of 
potential  can  easily  be  recorded  by  placing  the  patient's 
hands  in  jars  of  salt  solution  connected  by  wires  to  the  elec- 
trocardiograph. This  is  simply  a  very  sensitive  galvan- 
ometer, or  instrument  for  measuring  small  electrical  changes 
and  an  apparatus  for  recording  them  photographically. 
The  simplest  form  of  galvanometer  is  one  in  which  a  coil 
of  wire  is  placed  about  a  small  compass.  When  there  is 
a  flow  of  electricity  through  the  coil,  the  needle  of  the  com- 
pass moves  out  of  its  normal  position,  and  when  the  current 


20  THE  HEART  RHYTHMS 

ceases  the  needle  swings  back  again.  All  these  simple 
instruments  need  a  relatively  large  current  to  affect  them, 
and  the  chief  trouble  comes  from  the  inertia  of  the  recording 
device,  for  example  the  needle  of  the  compass,  which  takes 
some  time  to  swing  back  to  its  original  position,  and  so 
is  capable  of  recording  only  currents  which  occur  at  fairly 
slow  intervals.  In  the  electrocardiograph  an  Einthoven 
galvanometer  is  used,  which  is  made  on  a  different  prin- 
ciple from  the  compass  galvanometer.  Here  the  movable 
part  is  a  microscopic  thread  of  quartz  called  a  "string," 
which  is  suspended  vertically  in  a  strong  magnetic  field. 
When  a  minute  current  is  passed  through  it,  the  "string" 
is  deflected,  or  really  bent  laterally.  As  the  string  is  sup- 
ported at  both  ends,  has  a  very  small  mass,  and  moves 
only  a  fraction  of  a  millimeter,  it  has  very  little  inertia, 
and  can  record  impulses  up  to  many  hundred  times  per  min- 
ute. These  records  are  obtained  by  making  the  string 
opaque  with  a  coating  of  silver,  placing  it  in  a  beam  of  light 
which  throws  a  vertical  shadow,  magnified  by  a  microscope, 
onto  a  metal  plate  in  which  there  is  a  horizontal  slot.  This 
slot  allows  only  a  point  of  shadow  to  pass  through  to  a  mov- 
ing photographic  plate  or  film,  on  which  the  point  of  shadow 
writes  in  a  continuous  curve.  The  apparatus  is  shown 
diagrammatically  in  figure  7. 

When  curves  are  taken  of  a  normal  individual  with  this 
apparatus  they  are  found  to  be  of  the  following  character 
(fig.  8.) 

Two  distinct  curves,  or  as  we  call  them,  "complexes" 
are  seen  to  occur  at  regular  intervals.  The  first  complex, 
P,  is  a  small  upright  curve.  The  second  complex,  QRST, 
consists  of  a  high  vertical  curve  QRS,  followed  by  a  shght 
depression,  and  then  another  lower  and  broader  curve  T. 
Careful  analysis  shows  that  the  first  complex  P  is  caused 


DE\'ELOP]VIENT   OF   KNOWLEDGE   OF   HEART  RHYTHMS         21 


by  auricular  contraction,  and  the  second  complicated  curve 
or  ORST  is  of  ventricular  origin.  The  advantage  of  the 
curves  obtained  with  this  instrument  over  those  of  the  poly- 
graph will  be  seen  at  once.  In  the  polygraphic  curves, 
the  radial  tracing  gives  ventricular  beats  only,  and  the 
venous  cur\-e  gives  nothing  characteristic,  nothing  which 


Point  of  Shaaow. 


Stnn, 


'9- 


.-Slot 


L  3 


Line  of  Shadow 


Microscope 


C  3 


Lan 


Conaenser. 

'a  Bath 


Na^nQt. 


'■■Film 
Fig.  7.  Diagrammatic  representation  of  the  electrocardiograph. 


-Aj 


.<?   5, 


_2_L. 


Fig.  8.  A  diagrammatic  electrocardiogram  of  a  normal  rhythm.  The  auricular 
impulse  is  shown  by  the  upright  curve  P,  and  the  ventricular  imj^ulse  by  the 
complicated  curve  or  "complex"  QRST,  the  beginning  and  end  of  wliich  mark 
the  beginning  and  end  of  systole. 

when  the  curve  is  taken  separately  can  be  identilied  as 
being  of  ventricular  origin.  It  is  only  by  analyzing  the 
venous  tracing  in  relation  to  the  known  sphygmographic 
curve  that  the  origin  of  the  waves  in  the  venous  curve 
can  be  ascertained,  and  even  these  auricular  waves  are 
determined  by  a  process  of  exclusion.     In  the  electrocar- 


22 


THE  HEART   RHYTHMS 


W    ^ 


w  O 

H   a 


8  < 

u    ft 


W 


Ah      H 


o 


o  a 


DEVELOPMENT   OF   KNOWLEDGE   OF   HEART   RHYTHMS         23 

diogram  the  auricular  and  ventricular  complexes  can  be 
picked  out  at  once  by  their  characteristic  shapes,  and  when 
the  curves  are  well  taken  it  is  very  simple  to  interpret 
them,  as  for  example  that  of  figure  9,  where  it  is  e\'ident  to 
anyone  that  the  auricle  beats  twice  to  each  beat  of  the 
ventricle.  (Of  course  all  curves  are  not  as  simple  as  this 
diagrammatic  one,  as  some  auricular  beats  may  fall  in  some 

q  s 
J — - — ■ : 1 1 1 ' ' ' 1 1 — — —I 1 1 1 1 

Fig.  9.  A  curve  showing  the  simplicity  of  electrocardiograms  compared  with  the 
polygraphic  tracings.  Here  it  is  verj^  evident  that  the  auricle  beats  twice  to  each 
beat  of  the  ventricle. 

part  of  the  ventricular  complex  and  be  lost,  but  there  are 
ways  of  getting  out  of  these  difficulties  which  will  be  taken 
up  later.) 

This  short  review  of  the  instruments  in  use  will  make 
it  exident  why  it  is  simpler  to  begin  our  study  of  the  heart 
rhythms  with  electrocardiographic  curves,  rather  than  with 
those  of  the  supposedly  simpler,  because  smaller,  instru- 
ments, the  sphygmograph  and  the  polygraph. 


CHAPTER  II 

Five  Important  Elements  oe  the  Heart  Beat 

The  clinician's  training  is  so  closely  connected  with  heart 
conditions  of  an  entirely  different  nature  from  those  dealt 
with  in  this  book  that  it  is  hard  at  first  for  him  to  disre- 
gard his  old  ways  of  thinking,  and  to  think  of  the  heart 
abstractly,  and  not  as  it  actually  appears  with  its  valves, 
its  blood  flow,  etc.  In  the  study  of  rh3^thms  our  interest 
is  in  the  time  relation  only  of  the  contractions  of  the  four 
chambers  of  the  heart  and  for  our  purposes  the  heart  may  be 
represented  by  four  circles  as  in  figure  10  and  everything 
else  disregarded.  It  will  be  found  a  great  help  if  attention 
is  paid  to  this  heart  diagram  as  we  develop  it,  and  to  think 
of  the  time  relation  of  beats  of  these  circles  to  each  other, 
rather  than  of  the  auricles  and  ventricles  themselves. 

If  now  we  expose  an  animal's  heart  to  view  under  an  anes- 
thetic, five  important  points  can  be  made  out  by  simple 
observation  of  the  beating  heart.     These  are 

1.   THE     SIMULTANEOUS     CONTRACTION     OE    BOTH     AURICLES 
AND   BOTH  VENTRICLES 

In  the  first  place  it  will  be  noticed  that  both  auricles 
contract  simultaneously,  and  this  contraction  of  both  auri- 
cles is  followed  after  a  short  pause,  by  a  contraction  of  both 
ventricles.  One  never  sees  first  one  auricle  contract,  and 
then  the  other,  or  the  contraction  of  first  one  ventricle  and 
then  the  other,  but  the  two  auricles  beat  as  one  and  the  two 
ventricles  as  one  also.  The  two  auricles  are  really  one 
large  muscle  whose  cavity  is  divided  by  a  thin  septum,  and 
the  same  may  be  said  of  the  ventricles,  but  the  auricles  are 

24 


ELEMENTS  OF  THE  HEART  BEAT 


25 


distinctly  separated  from  the  ventricles  by  a  band  of  tissue, 
the  auricular-ventricular  septum.  As  both  auricles  beat 
as  one,  and  both  ventricles  beat  simultaneously,  we  may 
represent  the  heart  as  in  figure  11,  hereafter  speaking  of 
it  as  having  one  auricle  and  one  ventricle,  and  our  problem 
is  reduced  to  the  study  of  the  time  relation  of  contraction 


Fig.  10 


Fig.  11 


Fig.  10.  Diagrammatic  representation  of  the  four  heart  chambers,  the  time 
relations  of  contraction  of  which  we  are  dealing  with  in  the  study  of  the  heart 
rhythms. 

Fig.  11.  Reduction  of  the  heart  diagram  to  one  auricle  and  one  ventricle  as 
both  auricles  beat  as  one,  and  both  ventricles  as  one  also. 


of  these  two  chambers  to  each  other.  If  there  were  no 
factors  governing  the  beating  of  these  heart  chambers, 
the  number  of  rhythms  would  be  infinite,  but  fortunately 
for  us  there  are  a  few  limiting  factors  which  reduce  the  num- 
ber of  rhythms  to  a  comparatively  small  number,  and  these 
can  all  be  observed  in  the  beating  heart. 


26  THE  HEART  RHYTHMS 

2.  THE  RHYTHMICITY  OE  BEAT  OE  CARDIAC  MUSCLE 

The  exposed  heart  will  be  seen  to  beat  rhythmically  and 
regularly.  When  a  strip  of  muscle  is  cut  out  of  the  heart 
and  suspended  in  the  proper  solution  to  nourish  it,  or  if 
the  whole  heart  is  removed  and  supplied  by  an  artificial 
circulation,  the  heart  which  was  for  a  time  quiet  will  begin 
to  beat,  and  this  beat  will  occur  at  regular  intervals.  If 
the  rate  is  increased  or  decreased  by  various  methods, 
the  rhythm  will  still  be  regular. 

3.  THE  IMPULSE  EOR  CONTRACTION  OCCURS  AT  THE  POINT 
OF  GREATEST  IRRITABILITY 

It  will  also  be  noticed  that  the  auricle  beats  first  and  is 
followed  by  a  ventricular  beat,  then  there  is  a  pause,  and 
another  auricular  beat  occurs,  followed  again  after  a  short 
pause  by  a  beat  of  the  ventricle.  One  always  speaks  of 
the  ventricle  following  the  auricle,  but  it  is  possible  for  this 
order  to  be  reversed.  For  instance  if  we  cool  the  auricle 
of  a  beating  turtle's  heart,  without  cooling  the  ventricle,  the 
auricle  will  beat  more  and  more  slowly,  and  finally  the 
ventricle  will  beat  first,  and  be  followed  by  an  auricular 
beat.  That  is,  the  auricle  has  been  made  relatively  less 
sensitive,  or  as  we  say  "irritable,"  than  the  ventricle,  so 
much  so  that  the  ventricle  contracts  before  the  more  slug- 
gish auricle.  And  if  we  touch  either  the  auricle  or  the 
ventricle  with  a  stimulating  electrode,  or  any  stimulating 
substance,  we  may  by  increasing  the  irritant  cause  a  con- 
traction to  occur  before  the  normal  time,  while  in  patho- 
logical cases  conditions  occur  in  which  areas  in  the  auricular 
or  ventricular  muscle  become  abnormally  irritable,  and 
premature  beats  arise  from  them.  From  these  experiments 
and  others  which  will  be  taken  up  later,  it  appears  that  the 


ELEMENTS  OF  THE  HEART  BEAT  27 

beat  arises  from  the  point  of  greatest  irritability  in  the 
heart,  that  normally  the  auricle  becomes  more  irritable 
than  the  ventricle,  and  consequently  beats  first,  but  that 
artificially  the  ventricle  can  be  made  more  irritable  than 
the  auricle,  in  which  case  the  beat  will  arise  in  the  ventricle. 
Also  that  the  beat  may  occur  out  of  time  in  either  the  auri- 
cle or  ventricle,  if  these  chambers  are  irritated  by  some 
means. 

4.    THE   REFR-ACTORY   PERIOD   OF   THE   VENTRICLES 

We  have  seen  that  when  the  beating  heart  is  touched  by 
a  stimulating  electrode,  a  contraction  of  the  chamber  stimu- 
lated takes  place  at  once.  This  is  true  of  the  auricle,  but 
if  one  repeatedly  touches  the  ventricle  with  such  an  elec- 
trode, it  will  be  found  that  there  are  periods  in  which 
the  ventricle  will  not  respond  to  stimulation.  These  periods 
occur  during  a  ventricular  contraction  and  shortly  after. 
It  seems  as  if  the  ventricle  were  like  a  gun,  taking  a  certain 
length  of  time  to  reload  and  while  reloading  cannot  be 
fired.  The  auricle  on  the  other  hand  loads  so  quickly 
that  one  cannot  get  ahead  of  it,  and  it  will  fire  as  fast  as  the 
trigger  is  pulled.  This  period  in  which  the  ventricle  will 
not  respond  to  stimulation  is  called  the  "refractory  period," 
and  is  of  importance  because  in  abnormal  cases  in  which 
the  auricle  is  beating  very  rapidly  some  of  the  auricular 
impulses  reach  the  ventricle  when  it  is  in  this  refractory 
state,  and  no  ventricular  contraction  will  take  place. 

5.    THE    CONDUCTION   OF    IMPULSES    FROM  AURICLE   TO 
VENTRICLE 

We  have  noticed  in  the  beating  heart  that  the  auricular 
beat  is  followed  after  a  short  pause  by  a  beat  of  the  ventri- 
cle.    This  pause  is  normally  about  one-fifth  of  a  second. 


28  THE   HEART   RHYTHMS 

It  is  due  to  the  time  taken  for  the  auricular  impulse  to  pass 
from  the  auricle  to  the  ventricle.  That  such  an  impulse 
is  transmitted  from  one  of  these  heart  chambers  to  the  other 
can  be  easily  shown  in  the  turtle's  or  frog's  heart  by  means 
of  a  specially  devised  screw  clamp.  This  is  so  made  that 
any  desired  pressure  may  be  brought  to  bear  on  the  septum 
connecting  the  auricles  with  the  ventricles.  If  only  slight 
pressure  is  exerted,  the  time  taken  for  passage  of  the  auric- 


hurlcutar-  MdntrLculat 
Bundle. 


Fig.  12.  The  addition  of  the  auricular-ventricular  bundle  to  the  heart  diagram, 
in  order  to  deal  with  the  conduction  of  impulses  from  auricle  to  ventricle. 

ular  impulse  from  auricle  to  ventricle  is  increased  from 
one-fifth  of  a  second  to  two-  or  three-fifths  or  more.  Even- 
tually the  time  taken  for  the  passage  of  one  impulse  be- 
comes so  great  that  the  auricle  may  beat  twice  or  even  three 
or  four  times  to  one  beat  of  the  ventricle,  and  finally,  if 
the  clamp  is  completely  closed,  shutting  off  the  auricles 
from  the  ventricles  entirely,  these  two  chambers  beat  ab- 
solutely independently  of  each  other.     It  has  been  found 


ELEMENTS  OF  THE  HEART  BEAT  29 

that  these  impulses  are  transmitted  through  a  band  of 
speciaHzed  muscle  tissue,  running  from  auricle  to  ventricle, 
and  called  the  "auricular  ventricular  bundle"  or  "bundle  of 
His."  In  the  hiunan  heart  this  bundle  is  easily  seen  with  the 
naked  eye.  \Vhen  this  bundle  is  cut,  no  impulses  pass 
from  auricle  to  ventricle,  and  in  man  cases  are  observed 
in  which  the  ventricles  beat  independently  of  the  auricles 
and  autopsy  shows  a  gumma  or  arteriosclerotic  changes 
which  have  destro3^ed  the  bundle.  This  conduction  bundle 
is  then  of  importance  to  us  in  the  study  of  heart  rhythms 
and  we  must  add  it  to  our  heart  diagram  (figure  12). 

SUMMARY 

From  simple  observation  we  have  learned  that  the  heart 
beats  at  regular  intervals.  That  the  beat  arises  at  the 
point  of  greatest  irritability.  That  as  the  auricle  normally 
beats  first,  it  may  be  supposed  to  be  more  irritable  than 
the  ventricle,  but  that  this  condition  may  be  experimentally 
or  pathologically  changed,  and  the  auricle  or  ventricle, 
made  more  irritable  by  some  agent,  will  beat  out  of  time. 
That  the  auricle  recovers  quickly  from  a  beat,  and  is  always 
ready  for  the  next  one,  but  that  the  ventricle  is  relatively 
sluggish,  and  cannot  be  made  to  beat  again  until  a  certain 
amount  of  time  has  elapsed,  which  time  we  call  the 
"refractory  period. "  That  impulses  for  ventricular  contrac- 
tion arise  in  the  auricle,  and  are  transmitted  to  the  ventri- 
cle by  means  of  the  auricular  ventricular  bundle.  That 
when  this  bundle  is  impaired  by  any  means  a  greater  length 
of  time  is  needed  for  the  passage  of  auricular  impulses,  and 
when  the  bundle  is  destroyed  no  impulses  pass  from  auri- 
cle to  ventricle,  and  each  beats  quite  independently  of  the 
other. 


CHAPTER  III 

The  Division  of  the  Heart  Into  Functional  Areas  by 
Means  or  the  Electrocardiograph 

By  simple  observation  we  have  been  able  to  make  out 
the  chief  factors  which  control  the  heart  rhythm,  but  we 
have  a  far  better  method  of  studying  these  in  the  electro- 
cardiograph. If  we  anesthetize  an  animal  which  is  suitably 
connected  with  this  instrument,  and  expose  the  heart  to 
view,  the  electrical  disturbance  set  up  by  the  beating  heart 
will  be  recorded  in  a  curve  similar  to  that  of  figure  (13). 
We  have  already  said  that  the  complexes  P  are  caused 
by  auricular  impulses  and  the  complexes  QRST  by 
impulses  for  ventricular  contraction,  but  no  mention  was 
made  of  how  this  was  known.  In  the  first  place  when  an 
electrocardiogram  is  taken,  and  recorded  on  the  same  plate 
as  curves  made  mechanically  by  levers  attached  to  the 
auricle  and  ventricle,  it  will  be  found  that  the  P  waves 
occur  an  instant  before  the  mechanical  auricular  waves, 
and  that  the  complexes  QRST  also  occur  a  moment  before 
the  mechanical  contraction  of  the  ventricle,  from  which 
we  may  conclude  that  the  P  wave  represents  the  auricular, 
and  the  complex  QRST  the  ventricular  impulse.  When 
very  careful  measurements  are  made  it  is  found  that  the 
curves  recorded  in  the  electrocardiogram  always  preceded 
by  an  instant  the  corresponding  beat  of  the  heart.  Although 
we  do  not  know  just  what  the  electrical  phenomenon  is, 
which  goes  on  at  this  time,  it  seems  that  the  difference 
of  potential  is  not  caused  by  muscular  contraction,  as 
it  is  recorded  just  before  contraction  takes  place.  Also 
in  an  excised  heart  which  has  ceased  to  beat,  very  good 

30 


DmSION   INTO   FUNCTIONAL  AREAS 


31 


electrocardiograms  may  be  recorded.  We  believe  then 
that  the  electrocardiograph  records  impulses  for  contraction 
and  not  a  disturhauce  set  iip  by  contraction.  This  is  im- 
portant, because  the  size  and  shape  of  the  curve  is  in  no 
way  dependent  upon  the  size  and  force  of  the  beat.     A  good 


'II    ^ '  1 1  — 1^^' 


utfA'i ■HWMI^tf 


-Aj 


.<?  s. 


Fig.  13.  The  upper  figure  gives  normal  electrocardiograms  from  a  human 
subject,  showing  the  so  called  three  "leads"  described  on  page  (60).  This  is  done 
by  placing  the  electrodes  on  different  parts  of  the  body,  which  emphasizes  differ- 
ent portions  of  the  curve  as  seen  in  these  three  electrocardiograms  of  the  same 
subject.  The  lower  curve  gives  a  diagrammatic  one  which  will  be  used  entirely 
throughout  this  book  for  the  sake  of  simplicity.     Lower  curve  same  as  figure  8. 

example  of  this  is  that  of  premature  beats  of  the  ventricle 
which  give  such  a  small  pulse  wave  that  they  are  often  not 
felt  at  the  wrist,  and  are  spoken  of  as  skipped  beats.  The 
electrocardiogram  gives  an  abnormally  large  comi)lex  for 
these  small  beats,  and  a  normal  complex  for  the  large  j)ulse 
wave  which  follows  these.  This  relationship  can  be  seen 
in  figure  14.     Although  the  size  of  the  electrocardiographic 


32 


THE   HEART   RHYTHMS 


complex  is  of  no  importance  to  us  as  an  index  of  the  size 
of  the  beat,  the  shape  of  the  complex  is  of  the  greatest 
importance,  because  by  it  we  are  able  to  locate  the  origin 
of  the  impulse,  whether  in  the  auricle  or  the  ventricle,  and 
whether  it  arises  in  a  normal  or  abnormal  position  in  these 
heart  chambers.  That  the  shape  of  the  electrocardiographic 
impulse  is  characteristic  of  the  point  of  origin  of  the  impulse 


Time,  'js 

Fig.  14.  The  upper  curve  gives  an  electrocardiogram  of  an  ectopic  ventricular 
beat,  the  complex  of  which  is  much  larger  than  that  accompanying  a  normal 
beat,  while  the  radial  pulse  shows  a  small  pulse  wave  for  the  ectopic  beat. 
The  curve  is  given  to  show  that  the  size  of  the  wave  in  the  electrocardiogram  is 
in  no  way  proportional  to  the  actual  size  of  the  heart  beat. 


was  discovered  by  stimulating  the  exposed  heart  in  many 
places  with  single  induction  shocks,  which  caused  the 
auricle  or  ventricle  to  contract,  and  recording  the  impulses 
for  these  contractions  with  the  electrocardiograph.  In 
this  way  the  heart  was  functionally  mapped  out  into  the 
following  areas. 

1.  The  sino- auricular  node.  A  small  node  of  specialized 
muscle  tissue  located  at  the  junction  of  the  great  veins  of 
the  neck  with  the  auricles. 

2.  The  auricular-ventricular  node  and  bundle.  Situated 
at  the  base  of  the  auricle  at  the  beginning  of,  and  really  a 


DIVISION  INTO  FUNCTIONAL  AREAS  33 

part  of,  the  auricular-ventricular  bundle.  This  is  also 
made  of  the  same  tissue,  and  runs  from  the  auricular-ven- 
tricular node  to  the  ventricle,  where  it  divides  into  two 
branches,  one  going  to  each  ventricle. 

3.  The  auricular  musculature.  That  is,  the  mass  of 
cardiac  muscle  making  up  the  auricle,  and  which  we  cannot 
differentiate  into  any  particular  areas. 

4.  The  ventricular  musculature.  WTiich  is  the  general 
musculature  of  the  ventricle. 

Beats  may  arise  from  any  of  these  four  areas,  and  each 
beat  will  give  its  characteristic  complex  and  thus  be  located 
at  once.  These  areas  and  their  characteristic  complexes 
are  shown  in  figure  15.  It  will  be  seen  that  the  only  differ- 
ence in  the  impulses  arising  at  the  sino-auricular  node, 
and  those  from  the  general  musculature  of  the  auricle 
is  that  one  gives  upright  complexes,  while  the  others  are 
inverted.  If  we  consult  the  electrocardiogram  of  a  normal 
heart  (fig  13)  it  will  be  seen  that  the  auricular  impulse 
normally  arises  at  the  sino-auricular  node,  and  the  normal 
ventricular  impulse  at  the  auricular-ventricular  node.  If 
for  any  reason  an  impulse  arises  outside  these  normal  areas, 
we  speak  of  it  as  an  "ectopic"  impulse  of  auricular  or 
ventricular  origin. 

The  ectopic  ventricular  complexes  are  not  always  of  a 
very  distinguishing  shape,  but,  when  one  takes  an  electro- 
cardiogram in  which  normal  ventricular  complexes  are 
present,  it  is  usually  simple  to  differentiate  an  ectopic 
complex  from  a  normal  one.  As  a  rule  they  are  higher  and 
broader,  and  the  T  wave  may  be  inverted.  On  the  other 
hand  impulses  may  arise  in  one  of  the  branches  of  the  auric- 
ular-ventricular bundle  which  are  very  hard  to  tell  from 
the  normal.  But  these  are  minor  details  and  will  be  taken 
up  later;  the  point  of  interest  here  is  that  in  the  electrocardio- 


34 


THE   HEART   RHYTHMS 


graph  we  have  an  instrument  with  which  we  can  record 
the  time  relation  of  contraction  of  the  auricle  to  the  ventricle 
with  great  accuracy,  and  with  which  it  is  possible  to  tell 
whether  the  impulse  for  contraction  arises  at  the  normal  or 


wm  \mi« 


Mantrick 


Fig.  15.  Diagram  showing  the  division  of  the  heart  into  four  functional  areas 
by  means  of  the  electrocardiograph,  and  giving  the  characteristic  complexes  for 
each  of  these  four  areas. 


at  an  abnormal  place  or  "focus."  It  is  also  interesting  to 
note  that  it  has  been  possible  to  differentiate  these  areas 
in  the  heart  functionally  as  well  as  anatomically.  This 
instrument  gives  then  a  method  by  which  we  can  make  a 
complete  study  of  the  heart  rhythms,  and  allows  us  to 
classify  them  on  the  basis  of  point  of  origin  of  impulses. 


CKL\PTER  IV 

The  Classefication  of  Cardlic  Rhythms  on  the  Basis 
OF  Point  of  Origin  of  Impulses 

As  we  are  able  to  differentiate  the  heart  into  four  areas 
only,  from  which  impulses  may  arise,  we  can  have  only 
four  classes  of  cardiac  rhythms  based  on  the  point  of  origin 
of  impulses.  These  four  classes  are  as  follows:  (1)  Sino- 
auricular  rhythms,  (2)  ectopic  auricular  rhythms,  (3)  auricular- 
ventricular  nodal  rhythms,  (4)  ectopic  ventricular  rhythms. 

Let  us  take  up  each  of  these  rhythms  from  a  theoretical 
point  of  \dew,  calculating  from  our  knowledge  of  certain 
functions  of  cardiac  muscle  which  we  have  already  taken 
up,  and  our  knowledge  of  the  normal  electrocardiogram, 
what  rhythms  are  likely  to  occur  when  impulses  arise  in 
these  four  different  heart  areas. 

I .  siNO- auricular  rhythms 

By  simple  observation  of  the  beating  heart  we  found  that 
the  two  auricles  beat  as  one,  and  the  two  ventricles  as  one 
also,  and  that  we  could  consider  the  heart  for  our  purposes 
as  consisting  of  one  auricle  and  one  ventricle.  We  saw 
that  the  auricle  beat  first,  and  the  ventricle  one-fifth  of  a 
second  later.  We  concluded  that  the  ventricular  contrac- 
tion was  dependent  upon  impulses  received  from  the 
auricle  by  way  of  the  auricular-ventricular  bundle  because 
if  this  bundle  were  injured  the  ventricle  would  wait  for  the 
delayed  auricular  impulse.  And  if  the  bundle  were 
destroyed  no  further  relationship  between  the  auricles  and 
ventricles    could    be    made    out.      When    we    took    an 

35 


36  THE  HEART  RHYTHMS 

electrocardiogram  of  such  a  heart,  we  found  that  the 
auricular  complexes  were  characteristic  of  impulses  arising 
from  the  sino-auricular  node,  and  the  ventricular  im- 
pulses characteristic  of  others  arising  from  the  auricular- 
ventricular  node  started  by  impulse  waves  coming  from  the 
auricle.  Why  these  impulses  arise  we  do  not  know,  but 
we  do  know  that  the  rate  at  which  they  arise  varies  from 
time  to  time,  that  we  can  influence  this  rate  by  various 
means,  and  that  the  rate  is  under  nervous  control.  This 
is  shown  by  the  fact  that  stimulation  of  the  accelerator 
nerve  causes  an  increase  in  rate,  while  stimulation  of  the 
vagus  nerve  causes  a  decrease  in  the  heart  rate.  Certain 
chemicals,  as  calcium,  will  increase  the  rate  and  others,  as 
potassium,  will  decrease  it.  And  then  there  are  compli- 
cated factors  which  influence  the  heart  rate  that  cannot 
be  so  easily  analyzed,  as  for  instance  the  changes  in  exercise, 
the  increased  flow  of  blood,  the  increase  in  respiratory 
rate,  the  various  chemical  changes  in  the  blood,  etc.,  all 
of  these  things  are  liable  to  vary  the  heart  rate  and  although 
we  do  not  know  just  what  occurs  in  the  sino-auricular  node 
at  the  time  of  impulse  formation,  the  important  points  to 
be  noted  are  that  the  impulses  arise  at  regular  intervals, 
no  matter  what  variation  in  rate  occurs,  and  any  variation 
in  rate  of  rhythms  arising  at  the  sino-auricular  node  is  a 
gradual  variation.  There  is  never  any  sudden  break  in 
the  rhythms  as  that  which  occurs  in  other  conditions. 

We   have    four    uncomplicated    sino-auricular    rhythms 
which  are: 

1.  The  normal  heart  beat 

a.  Simple   tachycardia.    That    is,    a    normal   but    fast 
rhythm. 

b.  Simple  bradycardia.     A  normal  but  slow  rhythm. 


CLASSIFICATION  OF   CARDLA.C  RHYTHMS  37 

c.  Sinus  arrhythmia.  This  term  is  applied  to  gradual 
variations  in  rate  as  those  occurring  -with  exercise,  etc., 
but  chiefly  to  the  variation  in  rate  which  comes  mth  each 
respiration.  This  may  be  quite  marked  in  some  nervous 
young  people,  and  is  always  very  marked  in  children. 
It  is  an  entirely  normal  condition  and  simply  shoM^s  an 
active  respiratory  center. 

We  have  seen  that  an  electrical  or  chemical  stimulus 
applied  to  the  auricle  or  the  ventricle  would  cause  these 
chambers  of  the  heart  to  contract.  It  is  thus  easy  for  us  to 
conceive  of  some  point  in  either  the  auricle  or  the  ventricle 
becoming  stimulated  in  the  human  heart  by  some  patho- 
logical condition.  Such  conditions  do  occur  as  in  posioning 
by  chemicals,  from  changes  brought  about  by  infections, 
and  cellular  changes  in  the  cardiac  musculature.  They 
give  rise  to  beats  which  are  recognized  by  their  characteris- 
tic complexes  in  the  electrocardiogram  as  being  of  ectopic 
origin.  As  normally  the  impulse  for  a  cardiac  cycle  arises 
at  the  sino-auricular  node,  we  may  have  ectopic  impulses 
from  any  of  the  other  three  areas  of  the  heart,  that  is,  from 
the  auricle,  the  auricular-ventricular  node  and  bundle, 
and  from  the  musculature  of  the  ventricle,  and  clinically 
all  such  abnormalities  of  rhythm  occur.  Let  us  take  up 
each  of  these  three  types  of  rhythm  separately,  beginning 
with 

2.  Ectopic  heats  interrupting  the  normal  heart  beat 

a.  Ectopic  auricular  heats.  We  have  observed  that  one 
of  the  functions  of  cardiac  muscle  is  the  rhythmicity  of 
beat.  If  a  normal  rhythm  is  interrupted  by  an  ectopic 
auricular  beat  which  will  be  followed  in  the  normal  time  by 
a  normal  ventricular  beat,  it  will  interrupt  that  one  cardiac 
cycle,  but  the  auricle  will  begin  to  beat  again  normally 


38  THE   HEART  RHYTHMS 

at  once,  because  if  a  second  ectopic  impulse  does  not  occur, 
an  impulse  will  arise  from  the  sino-auricular  node  and  the 
heart  will  go  on  beating  normally.  The  extopic  beat  must 
occur  prematurely  or  otherwise  it  will  be  time  for  a  normal 
sino-auricular  impulse.  That  is  why  these  are  often  called 
"premature"  beats,  but  the  term  "extra  systole"  is  wrong 
as  there  is  no  extra  beat,  merely  a  premature  one. 

If  we  examine  the  electrocardiogram  of  such  a  case,  we 
find  a  curve  similar  to  that  in  figure  16.  The  regularly 
occurring  P  waves  followed  in  the  normal  time  by  normal 
ventricular  complexes  are  interrupted  at  X  by  an  auricular 
complex  occurring  prematurely.  It  will  be  noted  that  the 
complex  is  inverted,  which  at  once  tells  us  that  the  impulse 


p 


p 


Time.  'Is' 

Fig.  16.  Curve  of  an  ectopic  auricular  beat,  showing  the  inverted  auricular 
complex,  and  the  beat  arising  prematurely.  It  is  followed  by  a  normal  ventricular 
beat  in  the  usual  conduction  time. 

arose  from  an  ectopic  focus  in  the  auricle,  and  it  will  also 
be  noticed  that  this  ectopic  auricular  wave  is  followed  by 
a  normal  ventricular  complex.  The  reason  for  this  is  of 
course  evident,  because  auricular  impulses,  no  matter  of  what 
origin,  can  reach  the  ventricle  by  way  of  the  auricular-ventric- 
ular bundle  only,  and  in  so  doing  must  set  up  a  normal  im- 
pulse for  ventricular  contraction.  The  conduction  time  from 
auricle  to  ventricle  will  be  normal  as  there  is  no  abnormality 
of  the  conduction  bundle.  Following  the  ectopic  beat,  the 
heart  goes  back  to  its  normal  rhythm.  The  next  auricu- 
lar impulse  is  seen  to  be  of  sino-auricular  origin  and  may 
occur  at  the  normal  time  after  the  ectopic  beat,  sooner 
or  later  than  normal,  depending  entirety  upon  the  state  of 


CLASSIFICATION   OF   CARDIAC   RHYTHMS  39 

the  sino-auricular  node.  Attention  is  called  to  this  point 
in  contradistinction  to  ectopic  ventricular  beats,  which 
are  always  followed  by  a  pause  of  the  ventricle  of  a  definite 
length.  This  pause  is  due  to  the  ventricle  waiting  for  the 
next  auricular  impulse,  and  is  of  importance  in  polygraphic 
tracings  as  a  means  of  distinguishing  between  auricular  and 
ventricular  ectopic  beats,  but  it  has  no  significance  here 
in  electrocardiograms  because  the  shape  of  the  complex 
tells  us  at  once  whether  we  are  dealing  with  an  auricular 
or  a  ventricular  beat. 


Time  'js- 


FiG.  17.  Curves  of  a  premature  beat  arising  at  the  auricular- ventricular  node. 
It  will  be  noticed  that  the  electrocardiogram  shows  simply  an  absence  of  an  auric- 
ular impulse.  The  polygraphic  curve  on  the  other  hand  shows  a  small  arterial 
pulse  wave  at  the  time  of  the  premature  beat,  but  an  abnormally  high  c  or 
arterial  wave  in  the  venous  curve  at  this  time,  which  leads  one  to  believe  that 
the  auricle  and  ventricle  contract  simultaneously. 

h.  Ectopic  auricular -ventricular  nodal  heats.  In  the 
same  way  an  ectopic  beat  may  arise  from  the  auricular- 
ventricular  node,  and  interrupt  the  normal  rhythm.  It 
is  recognized  by  a  normal  ventricular  complex  occurring 
prematurely,  and  the  absence  of  an  auricular  complex. 
This  is  due  to  the  impulse  arising  at  a  point  about  equidis- 
tant from  the  auricle  and  the  ventricle  and  being  trans- 
mitted to  each  of  these  heart  chambers  in  the  same  length 
of  time  and  thus  stimulating  them  to  contract  at  once. 


40 


THE  HEART  KEYTHMS 


Such  a  beat  is  shown  in  fig.  17.  There  is  no  proof  from 
such  an  electrocardiographic  curve  that  the  auricle  does 
beat,  but  if  one  takes  a  simultaneous  tracing  with  the 
polygraph  it  will  be  seen  that  the  ventricular  curve  for  the 
premature  auricular-ventricular  nodal  beat,  in  the  radial 
tracing,  is  if  anything  smaller  than  normal,  while  the  cor- 
responding ventricular  curve  in  the  venous  tracing  is  much 
larger  than  normal.  As  no  auricular  wave  is  seen,  it  is 
supposed  that  the  reason  for  this  abnormally  large  ventric- 
ular wave  in  the  venous  curve  is  the  simultaneous  contrac- 


Timd  'Is". 


Fig.  18.  Same  as  figure  14.    Premature  ventricular  beat. 


tion  of  the  auricle  and  the  ventricle  sending  a  large  wave 
up  the  vein. 

c.  Ectopic  ventricular  beats.  Similarly  the  normal  rhythm 
may  be  interrupted  by  an  ectopic  beat  of  ventricular  origin. 
This  is  recognized  at  once  by  a  premature  ectopic  ventricular 
complex  occurring  in  the  curve,  as  shown  in  figure  18. 
It  gives  a  curve  which  is  of  interest  because  it  shows  that 
the  auricle  is  not  upset  in  its  rhythm  by  the  abnormal  ven- 
tricular beat,  but  continues  beating  regularly  in  its  usual 
manner.  The  ectopic  beat  occurred  prematurely  and  when 
the  next  beat  came  down  the  auricular- ventricular  bundle 
it  found  the  ventricle  in  the  " refractory " 'state  (see  p.  27) 


CLASSIFICATION   OF   C-ARDLA.C   RHYTHMS  41 

in  which  it  could  not  respond  to  stimulation.  The  ventri- 
cle thus  did  not  contract,  and  paused  until  the  next  auricular 
impulse  arrived.  Considerable  emphasis  is  laid  on  this 
pause  in  polygraphic  curves  as  it  gi^'es  a  method  of  distin- 
guishing auricular  from  ventricular  ectopic  beats.  It  is 
however  of  no  significance  in  our  study  here,  but  it  is  in- 
teresting to  note  that  there  really  is  no  pause  in  the  ventric- 
ular rhythm,  but  that  every  beat  is  on  time  except  the 
ectopic  beat  which  occurs  prematurely. 

These  ectopic  beats  of  auricular,  auricular-ventricular 
nodal,  or  ventricular  origin,  may  occur  singly  at  rare  intervals, 
or  frequently,  giving  a  regular  pulse  broken  occasionally 
by  a  single  beat,  or  a  pulse  which  is  so  irregular  that  it  is 
impossible  to  distinguish  it  from  the  absolute  irregularity  of 
auricular  fibrillation. 

n.   ECTOPIC  AURICULAR  RHYTHMS 

We  have  seen  that  it  is  possible  for  some  ectopic  focus  in 
the  auricle  to  become  irritated,  and  for  a  single  ectopic  beat 
to  arise  from  this  focus.  It  is  also  possible  for  this  irrita- 
tion to  become  so  constant  that  all  the  auricular  beats 
arise  from  this  point  and  none  from  the  sino-auricular  node, 
in  which  case  we  have  a  condition  of  an  ectopic  auricular 
rhythm.  An  electrocardiogram  of  such  a  rhythm  is  shown 
in  figure  19. 

During  the  establishment  of  the  ectopic  rhythm  one  may 
see  runs  of  ectopic  beats,  then  a  return  to  the  normal, 
then  ectopic  beats,  etc.,  but  when  the  ectopic  rhythm  is 
once  established  no  sino-auricular  impulses  can  be  made 
out  until  the  rhythm  suddenly  stops  and  returns  to  normal, 
when  all  of  the  auricular  complexes  are  again  of  the  sino- 
auricular  type. 


42  THE   HEART   RHYTHMS 

Auricular  impulses  of  ectopic  origin,  as  shown  by  the 
inverted  complexes,  arise  at  regular  intervals  and  are  fol- 
lowed in  the  normal  time  by  normal  ventricular  complexes. 
Although  all  ectopic  auricular  rhythms  are  fundamentally 
of  this  same  type,  they  fall  into  quite  sharply  defined 
clinical  groups  for  two  chief  reasons:  these  are,  the  rate 
at  which  they  occur,  and  the  mechanical  effect  on  the  cir- 
culation.   The  first  of  these  groups  is  that  of 

1.  Paroxysmal  tachycardia 

In  certain  cases  we  find  patients  with  the  heart  beating 
regularly  and  at  the  normal  rate  when  suddenly  they  are 
conscious    of    a    very    fast    throbbing    circulation.    They 


T/me  '/s 

Fig.  19.  Curve  of  an  ectopic  auricular  rhythm  in  which  all  the  auricular  com- 
plexes are  of  the  inverted  type  and  followed  in  the  normal  time  by  normal  ventricu- 
lar complexes. 

become  nervous,  frightened,  short  of  breath,  are  conscious 
of  palpitation,  and  the  veins  of  the  neck  are  usually  swollen. 
The  pulse  is  found  to  have  increased  enormously  in  rate, 
being  often  twice  what  it  was  before.  It  is  regular  and  an 
electrocardiogram  shows  a  regular  rhythm  in  which  all  the 
auricular  impulses  are  of  ectopic  origin,  and  each  auricular 
beat  is  followed  by  a  normal  ventricular  complex.  Such 
a  curve  is  shown  in  figure  19. 

The  attack  may  last  for  five  or  ten  beats,  several  minutes, 
or  many  hours,  and  leave  as  suddenly  as  it  came  on.  The 
cause  of  this  condition  is  unknown,  and  nothing  has  been 
found  which  will  shorten  an  attack  although  many  sub- 
stances are  believed  to,  but  the  electrocardiogram  shows 


CLASSIFICATION   OF   C-Aja)L4C   RHYTHMS  43 

US  definitely  that  the  patholog>-  of  the  condition  is  the 
ectopic  origin  of  all  auricular  impulses.  There  are  several 
points  of  interest  here.  In  the  first  place  it  will  be  noticed 
that  the  rate  is  much  above  the  normal,  roughly  180  to 
220  per  minute.  A  possible  reason  for  this  is  that  if  impulses 
arose  from  this  ectopic  focus  at  a  slower  rate  than  that  of 
the  normal  heart,  the  sino-auricular  node  would  break 
in  and  reestabhsh  itself.  Very  often  cases  are  found  in 
which  this  occurs.  There  mil  be  a  run  of  three  or  four 
ectopic  beats  and  then  a  few  normal  ones,  then  a  short  run 
of  ectopic  beats  and  finally  the  ectopic  rhythm  will  be  estab- 
hshed  with  all  the  impulses  of  ectopic  origin.  There  is 
howe^•er  no  gradual  variation  in  rate.  An  ectopic  rhythm 
assumes  a  rate  of  its  oa\ti,  and  beats  with  great  constancy, 
perhaps  because  it  is  not  under  any  nervous  control.  The 
actual  rate  at  which  these  impulses  arise  has  a  marked 
clinical  significance.  The  ventricle  is  able  to  follow  the 
auricle  up  to  rates  of  about  220  per  minute,  and  these  cases 
in  which  each  auricular  beat  is  followed  by  a  ventricular 
one  are  classified  as  paroxysmal  tachycardia,  the  name, 
paroxysms  of  rapid  heart  beat,  being  well  suited  to  the 
condition.  With  such  a  rapid  ventricular  rate  there  is 
necessarily  a  considerable  circulatory  disturbance  of  which 
the  patient  is  aware.  \\Tien  however  the  auricular  rate 
goes  above  220  or  thereabouts,  the  ventricle  is  unable  to 
follow  the  auricle  and  we  have  an  entirely  different  clinical 
picture,  which  has  been  given  the  name  of 

2.  Auricular  flutter 

The  patholog>'  of  this  condition  is  exactly  similar  to  that 
of  paroxysmal  tachycardia,  namely,  an  ectopic  auricular 
rhythm,  but  when  the  auricle  is  beating  at  a  rate  of  220  to 


44  THE  HEART  RHYTHMS 

450  per  minute  the  ventricle  can  no  longer  follow  it,  and 
we  have  two  or  three  auricular  beats  to  one  of  the  ven- 
tricle. In  such  a  case  although  the  auricular  rate  is  very 
great,  the  ventricular  rate  may  be  about  normal,  one 
hundred  or  so,  and  if  the  ventricle  happens  to  follow  an 
even  number  of  auricular  beats,  the  pulse  may  be  perfectly 
regular.  As  the  ventricle  is  pumping  about  the  normal 
amount  of  blood  through  the  body,  there  is  none  of  the 
circulatory  disturbance  which  is  seen  in  paroxysmal  tachy- 
cardia, and  the  patient  complains  only  of  a  curious  sensa- 

Timi'/s 

Fig.  20.  Curve  of  auricular  flatter  in  which  the  ventricular  rhythm  is  irregular 
on  account  of  the  ventricle  following  an  irregular  number  of  auricular  beats. 

Fig.  21.  Another  curve  of  auricular  flutter  in  which  the  ventricle  follows  every 
fourth  beat  of  the  auricle  and  gives  a  regular  ventricular  rhythm. 

tion  of  "fluttering"  about  the  heart,  and  a  sense  of  weak- 
ness. These  cases  are  often  missed  on  account  of  the  slow 
and  regular  pulse.  When  however  an  electrocardiogram 
is  taken,  the  condition  is  seen  at  once.  Figure  20  gives  a 
diagrammatic  curve  of  such  a  case.  Here  we  have  ectopic 
auricular  complexes  occurring  at  a  very  rapid  and  regular 
rate,  and  sometimes  two,  three,  or  four  auricular  beats 
followed  by  a  beat  of  the  ventricle.  In  figure  21  we  have 
the  same  condition,  in  which  however  the  ventricle  follows 
every  fourth  auricular  beat  and  gives  a  slow  and  regular 
pulse. 


CLASSIFICATION   OF   CARDIAC   RHYTHMS  45 

3.  Auricular  fibrillation 

If  the  auricular  rate  goes  above  450  or  thereabouts,  it 
is  impossible  for  the  auricle  to  contract  coordinately,  and 
it  goes  into  a  state  of  so  called  "fibrillation."  This  con- 
dition is  often  seen  in  laboratory  work  when  one  tries  to 
perfuse  a  heart  through  the  coronary  arteries.  The  auricle 
may  beat  a  few  times  and  then  it  fills  passively  with  blood 
and  twitches  in  many  minute  contractions  in  different 
parts  of  its  surface  at  once,  but  there  is  no  coordinate 


wv^ 


.-J  \/y^\^iy^\.,'-.-J\^^ 


r.a,^/, 


Fig.  22.  Three  curves  of  auricular  fibrillation.  It  will  be  seen  that  in  all  of 
them  the  ventricle  beats  absolutely  irregularly.  There  are  no  distinct  auricular 
complexes  seen,  but  in  curve  1  rapid  nearly  regular  oscillations  of  the  curve 
can  be  made  out.  In  curve  2  fewer  and  more  irregular  oscillations  are  seen 
while  in  curve  3  the  curve  is  practically  a  straight  line  between  ventricular 
beats. 

contraction  of  the  whole  auricle.  If  one  looks  at  it  care- 
fully it  will  be  seen  that  innumerable  contractions  are  taking 
place  in  small  groups  of  muscle  fibers.  When  an  electro- 
cardiogram is  taken  of  such  a  case  it  is  found  that  the  impulses 
are  arising  from  ectopic  foci  in  the  auricle  at  a  very  great 
rate,  500  per  minute  and  faster.  These  may  occur  regularly 
as  minute  auricular  complexes,  or  irregularly,  and  in  old 
cases  which  have  fibrillated  for  some  time  no  definite 
auricular  impulses  can  be  made  out.  Curves  of  all  three 
such  conditions  are  shown  in  figure  22.    It  seems  best 


46  THE   HEART  KEIYTHMS 

not  to  be  too  certain  in  trying  to  decide  just  which  is  a 
case  of  flutter,  and  which  is  fibrillation.  If  auricular 
complexes  occur  at  regular  intervals,  and  polygraphic 
tracings  show  regular  auricular  waves,  it  is  probable  that 
the  auricle  is  really  beating,  and  we  are  dealing  with  a 
case  of  flutter.  If  however,  we  happen  to  find  regular 
complexes  at  a  rate  of  600  per  minute,  and  no  well  marked 
auricular  waves  in  the  polygraphic  tracings  it  is  probable 
that  the  auricle  is  not  contracting  coordinately.  In  all 
cases  of  fibrillation  the  auricular  impulses  are  arising  at 
such  a  very  rapid  rate  that  it  is  impossible  for  the  ventricle 
to  follow  and  it  beats  in  an  absolutely  irregular  manner. 
The  irregularity  is  so  marked  and  so  persistent  that  these 
cases  have  been  recognized  for  many  years  before  any  means 
of  taking  tracings  were  found. 

Our  knowledge  of  impulse  formation  still  is  very  incomplete  but 
more  is  being  rapidly  found  out.  The  normal  auricular  impulse 
apparendy  arises  at  the  sino  auricular  node  and  spreads  in  a  wave 
over  the  auricle  in  all  directions  reaching  the  auricular  ventricular 
node  and  starting  there  another  impulse  for  ventricular  contraction. 
When  an  ectopic  auricular  impulse  arises  the  impulse  spreads  from 
this  point  in  waves  to  all  parts  of  the  auricle,  and  again  reaches  the 
auricular-ventricular  node  and  sets  up  a  ventricular  impulse.  If 
however  we  have  an  ectopic  auricular  rhythm  as  for  instance  paroxys- 
mal tachycardia  once  established  it  is  interesting  that  the  sino- 
auricular  node  which  may  be  supposed  to  be  quite  normal,  does 
not  break  in  on  the  ectopic  auricular  rhythm  and  interrupt  it. 
In  seeking  for  some  explanation  for  this  one  might  imagine, 
with  no  proof  of  it,  that  the  ectopic  impulse  wave  travelling  over 
the  auricle  reaches  the  sino-auricular  node  and  discharges  the  impulse 
which  is  building  up  there  before  it  has  become  of  sufficient  magni- 
tude to  discharge  of  its  own  accord  and  break  in  on  the  ectopic 
rhythm.  When  for  any  reason  the  ectopic  rhythm  fails  for  a  beat, 
the  sino-auricular  node  is  then  ready  to  discharge  and  again  assumes 
command  of  the  rhythm. 


CLASSIFICATION   OF   C.ARDLA.C   RHYTHMS  47 

In  auricular  flutter,  it  is  now  believed  that  the  cause  of  the  very- 
rapid  (roughly  450  per  minute)  rate  of  auricular  contractions  is 
not  due  to  impulses  arising  at  some  one  ectopic  focus  in  the  auricle 
but  that  there  are  so  called  "circus  contractions"  taking  place  in 
the  auricle.  It  was  found  some  years  ago  in  certain  types  of  medusa, 
or  contracting  "jelly  fish"  that  strips  cut  from  them  would  show 
a  wave  of  contraction  starting  at  one  end  and  passing  off  at  the  other. 
That  after  the  passage  of  a  contraction  wave  this  point  would  become 
refractive  and  refuse  to  respond  to  stimuli  for  some  little  time.  By 
cutting  out  a  circular  piece  or  ring  strip  of  tissue  it  was  possible 
to  start  a  wave  travelling  around  the  ring.  If  the  ring  were  of  suffi- 
cient length  when  the  wave  of  contraction  had  made  a  complete  circle 
and  reached  the  starting  point  again  the  refractory  stage  had  passed 
off  and  the  strip  w^as  ready  to  contract  once  more.  In  this  way  it 
was  possible  to  keep  up  a  wave  of  contraction  travelling  around  the 
ring  for  days.  This  same  phenomenon  has  been  observed  in  strips  cut 
from  the  hearts  of  the  dog  fish,  the  turtle,  and  the  dog,  and  lately  it 
has  been  experimentally  shown  in  flutter  produced  in  dogs  that 
there  is  such  a  wave  of  contraction  travelling  around  a  ring  at  the 
junction  of  the  great  veins  with  the  auricle.  Such  a  wave  in  its  rapid 
circular  movement  sends  off  waves  of  impulses  over  the  auricle  which 
cause  it  to  beat,  and  stimulate  in  turn  the  auricular  ventricular  node. 
As  long  as  this  vicious  circle  of  impulse  around  the  veins  occurs 
the  flutter  continues,  but  if  a  change  in  the  conduction  of  this 
strip  of  tissue  can  be  brought  about  which  will  break  up  the  ring  wave 
of  contraction  the  sino-auricular  node  will  then  have  a  chance  to  send 
out  its  impulses  to  the  auricle,  and  the  normal  rhythm  will  be  again 
established.  Such  treatment  has  already  been  successful  in  certain 
cases  but  does  not  lie  within  the  scope  of  this  book. 

In  auricular  fibrillation  it  is  still  undetermined  whether  the  enor- 
mous number  of  impulses  which  are  shown  in  the  electrocardiogram 
arise  from  muhiple  foci  of  stimulation  or  whether  they  are  complicated 
irregular  "circus  movements"  similar  to  those  of  auricular  flutter. 
For  our  purpose  of  studying  the  heart  rhythms  however  this  may  be 
disregarded,  and  three  types  of  auricular  ectopic  rhythms  considered, 
simply  from  the  different  clinical  pictures  which  they  present.  In 
the  first,  paroxysmal  tachycardia,  the  ventricle  follows  each  beat  of 
the  auricle,  and  gives  a  picture  of  a  rapid  circulation,  in  flutter  the 


48  THE  HEART  RHYTHMS 

ventricle  cannot  follow  the  fast  auricular  rate  and  the  pulse  may  be 
of  about  normal  rate  and  the  circulation  apparently  normal,  while 
in  fibrillation  the  auricular  rate  is  too  great  for  coordinated  auricular 
contractions.  Although  all  types  are  simply  due  to  ectopic  auricular 
impulses  they  cause  quite  different  clinical  pictures,  whichjustifi.es 
this  classification. 

m.  AURICULAR  VENTRICULAR  NODAL  RHYTHMS 

In  exactly  the  same  way  that  a  point  in  the  auricle  may 
become   irritated   and   give   rise   to   an   ectopic   auricular 

■J  u/'>«i^  L/>iii»J  l../^.iii.iJ  L/NmmJ 

Fig.  23.  Curve  of  an  auricular-ventricular  nodal  rhythm.  In  this  condition, 
which  is  very  rare,  the  impulse  for  contraction  arises  in  the  auricular-ventricular 
node,  and  the  auricles  and  ventricles  contract  simultaneously.  No  auricular 
complexes  are  visible. 


Fig.  24.  Curve  of  a  rare  case  of  ectopic- ventricular  rhythm  in  which  the  ventric- 
ular beats  are  of  ectopic  origin,  and  a  fairly  normal  rate,  and  the  ventricle  is 
beating  entirely  independently  of  the  auricle. 

rhythm,  the  auricular-ventricular  node  may  become  the 
point  of  greatest  irritability,  and  a  rhythm  may  be  set  up 
in  which  all  impulses  originate  from  this  node.  As  shown 
in  figure  23,  the  rhythm  will  be  regular,  on  account  of 
the  tendency  of  cardiac  muscle  to  beat  regularly,  and  the 
rate  will  be  very  limited.  In  fact  it  is  a  very  rare  condition 
and  the  reason  for  this  will  be  seen  if  we  think  of  just  what 
the  rhythm  means.  When  an  impulse  arises  at  the  auricu- 
lar ventricular  node,  the  auricle  and  ventricle  both  beat  at 
once.    If  the  rate  is  fast  the  ventricle  must  follow  each 


CLASSIFICATION   OF   CARDIAC   RHYTHMS  49 

impulse,  it  vdW  not  have  time  to  fill  properly  with  blood, 
and  the  circulation  wdll  not  be  properly  maintained.  If 
the  rate  is  very  slow,  the  sino-auricular  node  will  break  in 
and  start  the  normal  rhythm  again.  Thus  there  is  a 
comparatively  narrow  range  of  rates  in  which  it  would  be 
possible  for  such  a  rhythm  to  be  established.  As  has  been 
said,  the  condition  is  extremely  rare. 

IV.    ECTOPIC-VENTRICULAR   RHYTHMS 

In  the  same  way  that  a  point  in  the  auricle  may  become 
irritated  and  give  rise  to  an  ectopic  auricular  rhythm,  it 
is  conceivable  that  a  point  in  the  ventricle  might  also  be- 
come irritated  and  give  rise  to  an  ectopic  ventricular  rhythm. 
But  such  a  rhythm  would  have  to  be  rapid  or  else  the  sino- 
auricular  node  would  break  in  and  upset  the  rhythm.  We 
see  many  instances  of  this  in  which  there  are  runs  of  ectopic 
ventricular  beats,  and  then  a  return  of  the  normal  rhythm. 
If  the  runs  are  of  fairly  long  duration  they  are  very  upset- 
ting to  the  patient,  as  the  rapidly  beating  ventricle  cannot 
pump  sufficient  blood  to  maintain  the  circulation.  Certain 
very  rare  cases  of  temporary  ventricular  paroxysmal  tachy- 
cardia, flutter  and  fibrillation  have  been  reported,  which 
are  of  theoretical  interest  as  it  shows  us  that  all  the  possible 
rhythms  which  we  can  calculate  from  our  classification  of 
rhythms  do  occur,  but  for  all  practical  purposes  we  may 
say  that  ectopic-ventricular  rhythms  are  incompatible  with 
life.  The  one  case  of  ventricular  fibrillation  which  I  have 
seen  reported  was  one  in  which  an  electrocardiogram  was 
being  taken  from  a  patient  with  a  very  bad  heart.  Suddenly 
the  patient  became  pulseless,  stopped  breathing  and  was 
considered  dead.  The  electrodes  were  removed,  when 
suddenly  the  patient  began  to  breathe,  recovered  and  lived 
for  twenty  hours  longer.     On  development  of  the  film  it 


50  THE  HEART  RHYTHMS 

was  found  that  during  the  time  of  unconsciousness  the 
ventricle  went  into  a  state  of  fibrillation,  but  was  unable 
to  maintain  the  circulation  and  the  patient  became  uncon- 
scious and  pulseless.  It  is  probable  that  the  establishment 
of  an  ectopic-ventricular  rhythm  is  often  the  cause  of  sudden 
death. 

It  has  been  shown  that  we  have  rhythms  arising  from  each 
of  the  four  heart  areas.  We  have  shown  that  each  of  these 
rhythms  could  be  broken  in  on  by  impulse^  from  any  of  the 
other  areas.  We  have  pointed  out  that  there  is  a  hmit  to 
the  rate  at  which  the  ventricle  can  contract  and  still  main- 
tain an  efficient  circulation,  and  that  even  the  auricle  can 
not  contract  coordinately  above  a  certain  rate.  We  have 
considered  all  rhythms  arising  from  the  four  areas  into 
which  we  have  divided  the  heart,  and  seen  that  their  number 
is  Hmited  by  certain  functions  of  cardiac  muscle. 

Theoretically  it  is  possible  for  impulses  to  arise  from 
all  four  areas  at  once,  from  points  near  the  auricular  ven- 
tricular bundle  giving  curves  slightly  differing  from  nodal 
rhythms,  etc.  These  are  of  interest  theoretically,  but  are 
so  extremely  rare  that  they  can  be  disregarded  here.  It  is 
however  important  to  remember  that  one  may  sometime 
take  an  electrocardiogram  of  such  a  case,  and  then  it  is 
simply  necessary  to  plot  out  diagrammatically  the  time 
relations  of  auricles  to  ventricles,  the  origin  of  the  beats, 
and  see  where  this  rhythm  falls  in  the  above  classification 
in  which  it  must  find  its  place. 

There  is  a  condition  in  which  an  independent  ventricular  rhythm 
may  occur  however,  and  that  is  in  complete  heart  block  which  will 
be  taken  up  directly.  If  for  some  reason  the  auricular  ventricular 
bundle  is  functionally  destroyed  so  that  no  impulses  pass  from  auricle 
to  ventricle,  the  ventricle  is  left  to  take  on  a  rhythm  of  its  own, 
quite  independent  of,   and  uninterrupted  by  the  auricle.     In  an 


CLASSIFICATION   OF   CARDIAC  RHYTHMS  51 

uncomplicated  case  of  heart  block,  these  ventricular  impulses  are  of 
the  normal  type,  but  in  old  diseased  hearts  cases  have  been  reported 
in  which  there  is  a  regular  ectopic  ventricular  rhythm,  of  a  fairly 
normal  rate,  about  one  hundred  per  minute,  which  is  absolutely  in- 
dependent of  the  auricle,  which  beats  at  its  own  rate.  Such  a  con- 
dition is  shown  in  figure  24. 

SUMMARY   OF   ECTOPIC   RHYTHMS 

We  see  from  this  review  of  the  different  rhythms  that 
they  are  fundamentally  the  same,  although  giving  very 
different  clinical  results.  That  an  ectopic  rhvthm,  appar- 
ently  must  occur  at  a  faster  rate  than  normal  to  prevent 
the  sino-auricular  node  breaking  in  and  reestablishing  the 
normal  rhythm.  That  wheiLlh£jdaythmJs^once  set  up  it 
is  of  constant  rate,- perhaps  as  it  is  not  under  nervous 
controh_  That  in  the  ectopic  auricular  rhythms  we  have 
first  a  group,  paroxysmaljackycardia,  in  which  the  ventricle 
follows  JJTP  nnririp  Then  a  group  in  which  the  ventricle 
is  no  linger  f^l^lp  tn  k<^pp  pnre  with  the  auricle,  aiirictdar 
flutter y^  and  finally-ar-greup  in  which  the  rate  of  impulse 

formation  is;  c;r>  grpat  that  thp  annVle  itself  rnnnolxontract 

coordinatfily^—anjcL-goes  into  a  state  of  fibrillation.  In  all 
of  these  auricular  rhythms,  these  great  variations  of  rate 
are  not  extremely  dangerous,  as  the  ventricle  can  continue 
to  beat  at  such  a  rate  that  it  can  deliver  enough  blood  to 
keep  up  the  circulation.  WTien  however  the  rhythm  is 
one  in  which  the  new  rate  controls  the  ventricle  as  well 
as  the  auricle,  the  rate  at  which  the  rhythm  can  occur 
must  be  such  that  the  ventricle  is  able  to  maintain  the 
circulation,  that  is,  a  fairly  slow  rate,  and  this  rate  ap- 
parently cannot  occur  without  the  sino-auricular  node 
breaking  in,  except  in  rare  conditions,  as  for  instance 
auricular-ventricular  nodal  rhythm,  and  of  complete  heart 
block  in  cases  of  ectopic  ventricular  rhythm. 


CHAPTER  V 

Abnormalities  of  Conduction  prom  Auricle  to 
Ventricle 

We  have  seen  that  normally  the  auricular  impulse  is 
transmitted  from  the  auricle  to  the  ventricle  by  the  auric- 
ular-ventricular bundle  in  about  one-fifth  of  a  second. 
In  cases  of  poisoning  with  chemicals,  toxic  conditions  as 
pneumonia,  t3^hoid,  etc.,  this  bundle  may  be  functionally, 
partially  or  wholly  destroyed.  And  in  other  conditions 
of  pressure  or  destruction  by  new  growths,  syphilitic 
lesions,  etc.,  it  may  be  physically  injured  or  destroyed. 
Such  impairment  of  conduction  delays  the  conduction  of 
impulses  and  gives  rise  to  three  conditions  all  of  which 
are  different  degrees  of  the  condition  known  as  "heart 
block." 

1.  Increased  conduction  time.  In  the  first  of  these  the 
conduction  time  is  simply  increased;  instead  of  being  the 
normal  one-fifth  of  a  second  it  may  be  increased  to  two-  or 
three-fifths  of  a  second,  but  the  ventricle  follows  each 
auricular  beat. 

2.  Dropped  heats  or  partial  block.  If  however  the  injury 
to  the  bundle  is  greater,  the  delay  in  conduction  will  be 
so  great  that  the  auricle  will  beat  once  or  several  times  to 
one  beat  of  the  ventricle. 

3.  Complete  block,  idio-ventricular  rhythm.  And  finally 
if  the  bundle  is  completely  destroyed  the  auricle  will  beat 
at  its  own  rate  and  the  ventricle  will  take  on  an  independent 
rhythm  of  its  own.  The  first  two  of  these  conditions  are 
self-explanatory.  If  the  conduction  time  is  simply  increased 
the  pulse  will  be  of  the  same  rate  as  the  auricle  and  regular, 

52 


ABNORMALITY   OF   CONDUCTION  53 

and  the  abnormality  will  be  sllo^\Tl  by  the  use  of  some  in- 
strument only.  If  the  ventricle  follows  each  second  or  third 
beat  of  the  auricle,  the  pulse  vdW  be  slow  and  regular,  while 
if  it  follows  an  irregular  number  of  auricular  beats  it  will 
be  irregular. 

When  however  we  have  complete  block  a  very  distinct 
clinical  picture  is  found.  During  the  estabhshment  of  the 
independent  \'entricular  rhythm  the  patient  goes  through 
a  very  trying  transition  period.  He  will  pass  through  the 
first  two  stages  of  heart  block  with  no  great  difficulty, 
but  will  then  come  to  a  condition  in  which  the  ventricle 
must  w^ait  for  a  very  long  time  before  an  auricular  impulse 
will  pass  through  the  bundle  and  set  it  off.  At  first  this 
may  be  for  six  or  eight  beats  of  the  auricle.  The  ventricle 
will  become  greatly  distended  with  blood  and  the  patient 
will  become  conscious  of  the  pause  and  the  forcible  beat 
which  will  follow'.  As  the  block  to  the  passage  of  impulses 
becomes  more  complete,  there  will  be  a  still  longer  pause 
and  sometimes  it  will  be  as  much  as  ten  or  fifteen  seconds 
before  the  ventricle  will  beat  again.  During  this  time  the 
patient  will  become  unconscious  but  will  regain  conscious- 
ness as  soon  as  the  heart  begins  to  beat  once  more.  Such 
attacks  may  go  on  for  a  very  long  time  before  complete 
block  is  established,  and  the  ventricle  takes  up  a  rhythm  of 
its  own.  When  this  does  happen  the  ventricle  suddenly 
begins  to  beat  with  great  regularity,  and  at  a  very  slow 
and  characteristic  rate,  about  twenty-four  to  thirty  times 
per  minute.  The  patient  is  at  once  relieved  and  usually 
returns  to  very  good  health  and  may  go  about  for  many 
years  with  often  little  disturbance.  This  independent 
ventricular  rhythm,  usually  called  "  idio-ventricular  rhythm, " 
gives  normal  ventricular  complexes  in  the  electrocardiogram, 
which  means  that  impulses  arise  somewhere  in  the  bundle 


54  THE  HEART   RHYTHMS 

above  its  bifurcation.    Electrocardiograms  of  these  differ- 
ent rhythms  are  given  below. 

We  have  now  considered  rhythms  arising  from  each  of 
the  only  areas  into  which  the  heart  can  be  divided  at  present. 
We  have  considered  the  factors  which  limit  their  numbers, 
and  it  is  hoped  that  from  this  description  the  reader  will 
have  a  true  understanding  of  the  rhythms  of  the  heart. 
This  is  the  main  object  of  this  book.     The  rhythms  are 


Time.'/s 

R  R  R  R  R 

— A/U-^  .i.tiiii.i/V*wJU«^i.-M«A»>»JU*'''X*i»^.« ii/VlU^'S.i.» Ai«rlU 

,  a    ,       ,       ,       ,      <? 0  .  *»  .       .       .     g . 


p 


,JL 


Time  'Is 

Fig.  25.  Curves  showing  abnormalities  of  conduction  from  auricle  to  ventricle. 
I.  Showing  simple  increase  of  conduction  time  in  which  each  auricular  beat  is 
followed  after  an  abnormally  long  interval  by  a  beat  of  the  ventricle.  II.  Show- 
ing a  still  greater  disturbance  of  conduction  in  which  one  auricular  impulse  fails  to 
get  through  to  the  ventricle  and  this  ventricular  beat  is  dropped.  III.  Finally 
a  condition  where  the  ventricle  is  completely  cut  off  from  the  auricle  and  the  two 
beat  absolutely  independently  of  each  other. 


extremely  simple,  and  if  one  will  practice  constructing 
rhythms  in  which  beats  arise  from  the  different  areas, 
using  the  limiting  factors  of  regularity  of  beat,  conduction 
time,  refractory  period  of  the  ventricle,  and  rate  consistent 
with  life,  one  can  very  soon  satisfy  oneself  as  to  what 
rhythms  can  occur,  and  obtain  a  working  knowledge  of  the 
subject,  which  will  allow  him  to  reason  out  any  individual 


ABNORMALITY  OF  CONDUCTION 


55 


case,  rather  than  to  have  a  few  rhythms  learned  by  memory 
which  one  tries  to  apply  to  the  case  in  hand.  A  diagram- 
matic smmnary  of  the  rhythms  is  given  below. 


.y\. 


Sino  Auricular  Rhythms 
(1)  Normal  Rhythm. 

(a)  Simple  Tachycardia. 

(b)  Simple  Bradycardia, 

(c)  Sinus  Arrythmia 
(2)  Normal  Rhythm  Interrupted 

by 

(a)  Ectopic  Auricular  Beats. 

(b)  Auricular  Ventricular  No- 
dal Beats. 

(c)  Ectopic  Ventricular  Beats. 

Ectopic      Auricular 
Rhythms 

(1)  Paroxysmal  Tachycardia. 

(2)  Auricular  Flutter. 
(J)  Auricular  Fibrillation. 


-III.       Auricular       Ventricular 
Nodal  Rhythms 
Rare. 


Ectopic  Ventricular- 
Rhythms 

Incompatible  with  life  except 
in  rare  cases. 


V.  Abnormalities  oj  Con- 
duction in  any 
rhythm. 


Fig.  26.  A  diagrammatic  summary  of  the  heart  rhythms. 


PART  II 


CH.\PTER  I 
Interpretation  of  the  Electrocardiogram 

In  the  first  part  of  this  book  it  was  hoped  to  give  the 
reader  a  knowledge  of  the  heart  rhythms,  uncomphcated 
by  the  details  of  diagnostic  methods.  In  this  second  part 
the  object  is  to  tell  him  what  to  expect  from  the  use  of  the 
different  instruments  for  recording  the  heart  rhythms. 
A  detailed  description  of  their  use  is  however  not  attempted. 
It  is  assumed  that  the  electrocardiograph  gives  complete 
information  in  each  case.  It  is  then  merely  necessary  to 
point  out  the  usual  difficulties  in  obtaining  a  satisfactory 
record.  There  is  however  no  necessity  for  a  long  descrip- 
tion of  the  use  of  the  electrocardiograph.  The  instrument 
is  somewhat  similar  to  an  automobile.  Almost  anyone 
can  run  one,  but  to  obtain  a  knowledge  of  its  parts  takes 
considerable  study.  The  ordinary  student  or  practitioner 
cannot  afford  one  of  his  own  but  should  be  able  to  have 
an  electrocardiogram  taken,  examine  the  record  himself 
and  confirm  the  diagnosis  given.  In  order  that  he  will 
know  whether  the  record  has  been  well  taken  or  not  the 
following  few  essential  points  are  given. 

As  the  electrocardiogram  gives  us  characteristic  complexes 
for  impulses  arising  from  each  of  the  four  differentiated 
areas  above  mentioned,  and  shown  in  figure  15,  it  is 
possible  to  determine  at  once  from  such  a  curve,  the  rate, 
regularity,  source  of  impulse  formation  of  both  auricular 
and  ventricular  beats  the  length  of  conduction  time,  and 
the  interrelation  of  auricular  and  ventricular  beats.  Thus 
we  may  obtain  complete  data  from  an  electrocardiogram, 

59 


60  THE   HEART   RHYTHMS 

and  can  at  once  locate  the  condition  with  which  we  are  deal- 
ing in  the  above  classification  of  cardiac  rhythms. 

There  are  however  two  conditions  which  at  times  offer 
considerable  difficulties  in  the  interpretation  of  these  curves : 
those  in  which  auricular  impulses  are  not  clearly  indicated, 
and  other  conditions  where  auricular  impulses  are  obscured 
by  falling  in  the  ventricular  complex. 

The  first  of  these  conditions  is  often  remedied  by  taking 
the  so-called  three  leads.  If  two  electrodes  are  placed  at 
the  ends  of  a  bundle  of  muscle  fibers,  and  the  muscle  is  then 


Ri^hihm.  ^^^^  ""^  /efAA 


^rm. 


Left  Leo. 


Fig.  27.  Showing  the  different  angles  at  which  the  lines  of  electromotive  force 
cross  the  heart  in  the  so-called  "three  leads,"  Lead  I — ^R.  A.  and  L.  A.  Lead 
II— R.  A.  and  L.  L.    Lead  III— L.  A.  and  L.  L. 

made  to  contract,  a  much  greater  deflection  of  the  string  of 
the  galvenometer  occurs  than  when  the  electrodes  are  placed 
at  the  sides  of  the  bundle.  In  taking  an  electrocardiogram 
it  is  customary  to  "lead  off"  the  current  from  either  or 
both  hands,  or  from  the  right  or  left  hand,  and  the  left 
leg.  It  will  be  seen  from  figure  27  that  in  these  different 
leads  the  lines  of  electromotive  force  will  cross  the  heart 
at  different  angles.  One  of  the  leads  may  cross  the  heart 
at  a  more  advantageous  angle  than  another,  so  that  in  case 
auricular  complexes  are  not  clearly  seen  in  one,  it  is  well  to 
try  another  until  a  satisfactory  result  is  obtained. 


THE  ELECTROCARDIOGRAM  61 

In  case  the  auricular  wa\-es  are  thought  to  be  hidden  in 
the  ventricular  complexes,  these  three  leads  may  be  used  in 
hopes  of  depressing  a  portion  of  the  ventricular  curve  and 
bringing  out  the  auricular  complexes.  If  this  is  not  possible 
a  change  in  rate  may  be  attempted  by  cautious  means 
(making  certain  of  course  that  it  will  not  'be  injurious  to 
the  patient).  If  these  means  also  fail  it  is  well  to  take  a 
long  strip  of  curve  to  see  if  any  irregularities  occur,  in  which 
case  the  auricular  complex  may  show  up  between  the  beats. 
If  the  heart  remains  perfectly  regular  the  chances  are  very 
great  that  the  auricle  is  beating  and  controlling  the  rhythm. 
WTiether  the  auricular  impulses  are  of  sinus  or  ectopic  origin 
can  however  not  be  ascertained  in  that  condition.  One 
is  then  left  to  judge  whether  this  is  the  case  or  not  by  other 
means,  as  the  history,  s}Tnptoms,  change  from  day  to  day, 
which  of  course  does  not  come  directly  under  the  heading 
of  interpretation  of  curves. 

The  beginner  may  adopt  some  such  routine  examination 
of  curves  as  the  follo\\ing  in  order  not  to  overlook  anything. 

1.  Examine  the  time  curve.  See  if  the  intervals  are 
equal,  in  other  words  whether  the  paper  runs  at  an  even 
rate.     This  is  important. 

2.  Locate  auricular  complexes  if  possible. 

3.  Locate  ventricular  complexes. 

4.  If  auricular  complexes  are  present  (they  are  absent 
in  auricular  fibrillation  and  auricular-ventricular  nodal 
rhythm  only)  see  if  they  are  of  normal  or  ectopic  origin, 
equidistant,  or  irregular.     Note  the  rate. 

5.  See  if  a  ventricular  complex  follows  each  auricular 
complex  and  note  the  length  of  conduction  time.  (The 
distance  between  auricular  and  ventricular  complexes.) 
See  if  this  is  normal  (about  one-fifth  second)  and  if  it  is 
constant  throughout  the  curve. 


62 


THE   HEART  RHYTHMS 


With  these  data  we  can  determine  the  rate  and  rhythm 
of  the  auricle  and  of  the  ventricle,  and  the  time  relation  of 
contraction  of  one  to  the  other.  That  is,  whether  we  have 
a  regular  auricular  rhythm,  a  gradual  variation  in  rate  of 
auricular  rhythm  (sinus  irregularity)  or  whether  the  regular 
rhythm  is  suddenly  broken.  We  can  tell  the  same  of  the 
ventricle.  From  the  conduction  time  we  can  determine 
the  condition  of  the  conduction  system.  Finally  we  note 
the  form  of  complexes,  whether  of  normal  or  ectopic  origin. 
We  then  decide  which  of  the  five  general  types  of  rhythm 
we  are  dealing  with  (sino-auricular,  ectopic  auricular, 
auricular-ventricular  nodal,  ectopic  ventricular,  or  heart 
block). 


X^-JU^-Ju 


*i      M     s 


H      S 


Fig.  28.  Diagrammatic  scheme  for  showing  auricular  and  ventricular  beats 
and  the  conduction  time.  The  upper  heavy  line  represent  auricular  contrac- 
tion and  the  lower  ventricular,  while  the  slanting  line  gives  the  conduction  time. 

In  compHcated  cases  it  may  help  the  beginner  to  represent 
the  curve  diagrammatically.  A  strip  of  paper  may  be 
laid  along  the  curve  as  in  figure  28  and  the  time  of  auric- 
ular and  ventricular  complexes  marked  off  on  it  in  vertical 
lines.  Connect  the  auricular  to  ventricular  lines  by  slant- 
ing lines  as  in  the  figure,  and  let  these  represent  the  conduc- 
tion time.  In  this  case  it  is  evident  that  the  auricle  is 
beating  regularly,  that  the  conduction  time  gradually  in- 
creases until  one  ventricular  beat  is  dropped.  This  method 
of  diagrammatically  representing  the  beats  is  much  used, 
and  the  construction  of  such  a  curve  may  make  it  more 
simple  to  see  just  what  condition  we  are  dealing  with  in 
compHcated  curves. 


THE  ELECTROCARDIOGRAM  63 

One  other  point  remains  to  be  spoken  of,  and  that  is  the 
form  of  ventricular  complexes.  One  needs  to  look  at 
very  few  electrocardiograms  to  see  that  the  form  of  the 
complexes,  especially  those  of  ventricular  origin,  vary 
greatly.  It  is  usually  simple  to  tell  whether  they  are  of 
normal  or  of  ectopic  origin,  but  it  is  not  simple  to  tell  just 
where  they  arise.  By  a  careful  study  of  these  complexes, 
taken  ^^ith  the  different  leads,  information  may  be  obtained 
as  regards  right  and  left  cardiac  hypertrophy,  lesions  of 
the  right  and  left  bundle,  the  position  of  the  heart,  etc.  This 
information  although  valuable,  has  nothing  to  do  with 
cardiac  rhythm,  and  the  reader  is  referred  to  more  advanced 
books  for  the  study  of  these  problems. 


CHAPTER  II 

The    P0LYGIL4PH,   Sphygmograph,   and   Pulse 

Instruments.  In  studying  tracings  taken  with  these  in- 
struments we  are  deahng  with  curves  made  by  recording  the 
mechanical  filhng  of  the  vessels  by  blood  pumped  from  the 
different  heart  chambers.  It  is  at  once  evident  that  these 
curves  will  give  only  the  time  of  contraction  of  auricle  and 
ventricle,  and  not  the  point  of  impulse  formation  as  shown 
in  the  electrocardiogram  (as  both  a  normal  and  ectopic 
beat  will  give  an  equally  good  pulse  wave).  Furthermore 
the  shape  of  the  curves  is  not  characteristic,  so  that  by 
glancing  at  a  tracing  we  cannot  pick  out  auricular  and 
ventricular  waves.  Finally  the  recording  and  shape  of 
these  curves  depends  upon  the  sensitiveness  of  the  appara- 
tus, the  skill  of  the  operator  in  adjusting  it,  and  extraneous 
factors  such  as  movements  of  the  patient,  the  apparatus, 
etc.,  all  of  which  may  cause  extra  waves  in  the  curves 
or  absence  of  expected  waves.  The  recording  and  inter- 
pretation of  polygraphic  tracings  will  be  found  to  be  much 
more  difficult  and  inexact  than  the  making  and  interpre- 
tation of  electrocardiograms. 

The  most  important  and  helpful  point  in  the  interpre- 
tation of  these  curves  is  to  know  exactly  how  many  points 
in  the  curve  can  be  fixed  with  certainty,  how  many  more 
by  one's  knowledge  of  heart  physiology,  and  how  much 
must  be  left  to  one's  judgment.  The  interpretation  of 
polygraphic  tracings  is  not  a  complete  and  exact  science. 
Certain  facts  can  be  established,  often  enough  for  a  complete 
interpretation,  more  often  however  the  facts  of  the  curve  are 
not  enough  to  make  a  diagnosis  certain  but  can  be  used  as 
a  diagnostic  aid  only. 

64 


POLYGRAPH  AND   SPHYGMOGRAPH 


65 


The  instruments  in  use  are  of  several  types  but  all  are 
based  on  two  principles.  In  one  the  radial  pulse  is  taken 
by  means  of  a  small  spring  which  rests  on  the  radial  artery. 
The  pulse  w^ave  raises  the  spring,  compresses  the  air  in  a 
tambour  connected  to  it,  and  transmits  this  wave  to  a 
second  tambour  to  which  is  attached  the  writing  lever. 

In  the  other  t>^e  an  arm  cuff  is  used,  which  is  placed 
about  the  arm  over  the  radial  artery.     This  cuff  is  attached 


Fig.  29.  Diagrammatic  scheme  of  arm  cuff  method  of  recording  the  arterial 
pulse  curve.  The  letter  a  represents  the  arm  cuff;  b  the  bulb  to  fill  it  with  air; 
c  the  manometer  with  which  to  take  the  arterial  pressure;  d  a  rubber  ball  to 
take  up  this  heavy  pressure;  e  a  glass  container  in  which  the  pulse  waves  reaching 
d  are  transmitted  to  the  air  at  low  pressure  to  the  tambour  /,  which  records  them 
by  means  of  the  lever  g  on  the  revolving  drum. 

by  a  rubber  tube,  to  a  recording  tambour.  On  account  of 
the  high  arterial  pressure  a  bulb  is  interposed  between  the 
cuff  and  the  tambour  to  take  this  pressure  off  the  recording 
tambour  as  shown  in  figure  29.  In  this  figure  a  is  the  arm 
cuff,  h  the  bulb  to  fill  it  with  air,  c,  the  manometer  to  re- 
cord the  pressure,  and  d,  the  bulb  to  take  up  this  pressure. 
WTien  the  cuff  is  blown  up  to  the  proper  pressure  (some- 
where between  the  diastolic  and  systolic  pressures),  each 


66 


THE  HEART   KEYTHMS 


pulse  wave  causes  d  to  expand,  compresses  the  air  in  e, 
a  closed  glass  chamber  connected  with  the  tambour  / 
and  the  writing  lever  g,  which  records  each  pulse  wave. 
A  mercury  manometer  is  also  attached  to  the  instrument, 
which  is  useful  in  taking  the  blood  pressure,  but  also  is 
of  help  because  the  cuff  may  be  blown  up  until  the  best 
arterial  pulse  is  obtained,  the  pressure  recorded,  and  then 
the  venous  tambour  arranged.     When  the  time  comes  to 


19 

No.  43076 
Fig.  30.  The  Mackenzie  polygraph,  with  horizontal  pens. 

make  the  arterial  tracing  it  is  only  necessary  to  blow  up 
the  cuff  to  the  pressure  noted  before,  turn  on  the  tambour, 
and  one  is  sure  of  obtaining  a  good  radial  curve. 

The  first  of  these  methods  requires  more  time  and  trouble 
in  adjusting  the  spring  to  the  pulse.  This  is  often  annoying 
when  trying  to  take  a  tracing  quickly  after  exercise,  etc. 
The  latter  method  requires  no  skill  in  adjustment  as  the 
cuff  is  merely  shpped  over  the  arm  and  blown  up.  It 
can  be  attached  at  once  and  gives  beautiful  records. 


POLYGRAPH  AND   SPHYGMOGRAPH 


67 


c    &- 


3     C 
tn     TO 


C 

a   E 


W  in 
3     C 

s  ° 

IS 

OJ  ■'-> 
C  ^ 
«    in 

"  .S 
•J      10 

S       to    !5 


I  "^ 

(I)  4> 

S  o 

.§  e 

N  ■" 


68 


THE   HEART   RHYTHMS 


The  venous  pulse  is  recorded  by  placing  a  small  glass 
funnel  or  other  cup  receiver,  over  the  veins  of  the  neck. 
The  air  is  transmitted  to  a  tambour,  and  writing  lever 
similar  to  that  used  with  the  radial  pulse,  and  described 
on  page  65. 

The  tambours  are  all  of  the  same  general  type,  but  some 
use  a  horizontal,  others  a  vertical  pen.     The  horizontal 


No,  43104 


Fig.  32.  The  Jaquet  polygraph,  a  very  beautiful  instrument,  which  is  attached 
to  the  wrist. 

pen  is  good  when  one  is  accustomed  to  it,  but  with  the  be- 
ginner it  is  constantly  coming  off  the  paper.  With  the 
vertical  levers  the  pens  hang  on  the  paper  and  cannot  come 
off,  and  when  in  good  condition  give  excellent  curves. 

The  two  types  of  instrument  most  often  used  are  the 
Mackenzie  with  horizontal  pens,  which  is  a  beautiful 
machine  and  compact,  and  a  newer  type  the  Zimmermann 
(fig.  31),  with  arm  cuff  attachment,  vertical  pens,  and  blood 


POLYGILA.PH   AND    SPHYGMOGRAPH  69 

pressure  attachment.  This  is  by  all  means  the  simplest 
machine  as  no  difficulty  is  found  in  obtaining  a  good  radial 
tracing.  The  pens  cannot  come  off  the  paper,  and  the 
instrument  is  so  constructed  that  tracings  may  be  made  on 
rolls  of  smoked  paper,  or  on  plain  paper  with  ink. 

Another  very  beautiful  instrument  is  the  Jaquet  (fig. 
32)  which  is  a  deHcate  httle  affair  which  is  attached  to  the 
wrist.  One  has  to  use  small  strips  of  smoked  paper,  and 
although  it  is  as  beautifully  built  as  a  watch  it  is  not  as 
convenient  for  ordinary  use. 

THE  RADIAL  PULSE 

Let  us  return  once  more  to  our  original  diagram  of  the 
heart  (fig.  33). 

We  see  that  the  left  ventricle  is  the  only  heart  chamber 
which  sends  blood  into  the  aorta,  and  consequently  all 
arterial  pulses  are  indices  of  left  ventricular  contraction  only. 
Any  arterial  pulse  curve  (that  is  radial,  brachial,  temporal, 
etc.)  will  show  the  following  points  (fig.  34). 

An  upstroke  (1),  a  sharp  apex  (2),  a  plateau  broken  by 
a  notch  (3),  a  downstroke  reaching  normal  at  (4),  Let  us 
now  see  to  what  causes  these  various  parts  of  the  curve 
are  due. 

The  upstroke  (i)  is  due  to  ventricular  systole,  sending 
a  wave  of  blood  down  the  artery.  The  end  of  this  upstroke 
is  seen  in  a  sharp  point  (2),  which  will  vary  in  shape  and 
size  with  the  weight  of  the  lever,  the  sensitiveness  of  the 
tambour  used  etc.  It  is  not  then  a  constant,  and  is  of 
no  importance.  The  notch  (J)  is  the  so  called  dicrotic 
notch.  It  occurs  at  the  end  of  systole  at  the  time  when 
the  ventricle  relaxes.  Various  explanations  have  been 
given  for  its  origin  but  we  may  think  of  it  unscientifically 


70 


THE  HEART  RHYTHMS 


Mackenzie  Ink  Polygraph,  New  American  Model 


Jaquet  Portable  Polygraph 


POLYGRAPH  AKD   SPHYGMOGRAPH 


71 


as  a  back  kick  of  the  blood  when  the  ventricle  stops  forcing 
it  into  the  aorta,  and  relaxes,  the  arterial  pressure  becomes 
then  relatively  higher  than  in  the  ventricle,  and  slaps  back 


fiorta  and  Arte  rial  PJses. 

Fig.  a.  Same  as  figure  1.     Diagrammatic  representation  of  the  origin  of  the 
arterial  pulse. 


Fig.  34.  Same  as  figure  3.  Three  types  of  arterial  pulse  curves  showing  the 
different  forms  of  the  curve  which  are  unimportant  as  long  as  the  beginning  of  sys- 
tole (/)  and  the  dicrotic  notch  (J),  the  end  of  systole,  are  to  be  seen. 

on  the  aortic  valves.  In  any  case  it  occurs  at  the  end  of 
systole.  The  point  (4)  where  the  curve  returns  to  normal, 
is  a  variable,  it  depends  upon  how  full  the  arteries  are  when 


72  THE  HEART  EHYTHMS 

the  pulse  wave  comes  down  it,  etc.  It  is  of  no  use  to  us 
and  should  be  entirely  disregarded. 

In  the  radial  pulse  curve  we  have  then  two  points  of 
importance  only,  everything  else  may  be  disregarded. 
These  two  points  are: 

1^  The  upstroke  marking  the  beginning  of  ventricular 
systole. 

2.  The  dicrotic  notch,  marking  the  end  of  ventricular 
■systole. 

Curves  should  be  so  taken  that  these  two  points  come  out 
clearly.  If  they  do  not  the  curve  is  of  no  use.  Whether 
the  rest  of  the  curve  is  large  or  small  is  merely  a  matter  of 
beauty,  but  is  of  no  consequence. 

THE   VENOUS   PULSE 

In  taking  a  venous  curve  the  patient  should  lie  flat 
(if  possible),  with  a  small  pillow  under  the  head  in  such  a 
position  that  the  sterno-cleido  mastoid  muscle  is  relaxed. 
The  receiver  is  best  placed  over  the  lower  end  of  this  muscle 
on  the  right  side,  just  above  and  at  the  inner  end  of  the 
clavicle.  One  is  tempted  to  place  the  receiver  higher  up 
where  the  veins  are  more  prominent,  but  in  most  cases 
this  will  not  give  as  good  a  curve.  No  fixed  rule  can  how- 
ever be  given  for  this,  and  the  best  position  will  have  to 
be  found  for  each  patient. 

Having  obtained  a  venous  tracing  we  find  a  curve  in  the 
normal  individual,  similar  to  that  shown  diagrammatically 
in  figure  35.  An  actual  polygraphic  tracing  is  shown  in 
figure  4.  The  shape  of  the  curve  is  of  no  importance, 
and  it  varies  in  each  case,  and  in  the  same  case  depending 
entirely  upon  the  adjustment  of  the  instruments.  It  is 
however  necessary  to  know  what  to  look  for  in  these  curves, 


POLYGRAPH  AND   SPHYGMOGRAPH  75 

and  to  take  them  with  the  object  of  bringing  out  the  es- 
sential points  instead  of  making  a  beautiful  appearing 
tracing  which  may  lack  the  few  points  necessary  for  a 
diagnosis.  Nothing  very  definite  can  be  made  out  of 
such  a  curve.  The  waves  are  not  of  characteristic  shape 
or  size,  we  cannot,  therefore,  identify  any  one  of  them  as 
being  due  to  some  particular  portion  of  the  cardiac  cycle. 
It  is  then  evident  that  the  venous  curve  alone  is  of  Httle 


Fig.  35.  Same  as  figure  4.  A  normal  polygraphic  tracing  showing  that  the 
venous  curve  gives  no  waves  of  characteristic  shape  by  which  the  auricular  beats 
could  be  distinguished  from  those  of  the  auricle. 

value  to  us,  and  before  taking  up  the  analysis  of  such 
curves  let  us  represent  diagrammatically  (fig.  36)  a  cardiac 
cycle,  the  heart  being  shown  as  ha\dng  but  one  auricle 
and  one  ventricle,  and  the  great  veins  as  a  tube  entering 
the  auricle  from  above. 

If  one  uses  the  imagination  a  trifle  it  may  be  possible  to 
make  out  from  this  series  of  figures  the  sequence  of  events 
taking  place  in  the  auricle  and  ventricle,  and  the  cause  of 
the  different  venous  and  radial  pulses. 


74 


THE  HEART   RHYTHMS 


At  (i)  both  auricle  and  ventricle  are  partially  filled  with 
blood.  At  (2)  the  auricle  contracts,  as  indicated  by  the 
heavy  outline,  and  forces  its  blood  into  the  ventricle, 
distending  the  latter.  This  contraction  of  the  auricle  is 
accompanied  by  a  back  wave  up  the  vein,  and  a  rise  in  the 


Fig.  36.  Diagrammatic  scheme  showing  the  cause  of  the  venous  and  arterial 
pulse  waves.  At  (1)  both  auricle  and  ventricle  are  partially  filled  with  blood.  At 
(2)  the  auricle  contracts  as  shown  by  its  heavy  outline,  and  forces  blood  into 
the  ventricle,  distending  it.  At  the  same  time  it  sends  a  wave  up  the  veins  to  the 
neck  and  causes  a  rise  in  the  venous  curve,  the  a  wave.  At  (J)  the  auricle  relaxes 
as  shown  by  the  irregular  outline  and  the  ventricle  contracts  and  drives  the  blood 
out  into  the  aorta.  This  contraction  causes  a  wave  in  the  venous  curve,  the  c  wave 
at  the  beinning  of  systole.  The  ventricular  pulse  wave  does  not  reach  the  wrist 
until  one-tenth  of  a  second  after  the  corresponding  wave  in  the  neck,  due  to  the 
time  taken  to  travel  there.  At  (4)  the  ventricle  is  still  contracting  and  the  auricle 
filling  with  blood.  This  causes  backing  up  of  blood  in  the  veins  and  a  rise  in  the 
venous  curve.  At  (5)  the  ventricle  relaxes,  end  of  systole,  and  the  blood  falls 
from  the  auricle  into  the  ventricle  causing  a  sharp  drop  in  the  venous  curve,  the 
V  wave  (really  a  drop  in  the  curve).  At  the  same  time  the  dicrotic  notch  occurs 
in  the  arterial  pulse.  At  (6)  both  the  auricle  and  ventricle  are  passively  filling 
with  blood,  and  at  (1)  the  cycle  is  begun  again  by  contraction  of  the  auricle. 


POLYGR.\PH  AND    SPHYGMOGILA.PH  75 

venous  curve  at  (a).  The  letter  {a)  is  used  in  these  curves 
to  denote  auricular  waves.  It  is  placed  at  the  upstroke 
of  the  waves  as  are  all  polygraphic  measurements,  as  the 
end  of  the  upswing  depends,  as  before  stated  upon  the  sen- 
sitiveness of  the  writing  lever,  etc.,  and  is  not  constant. 
The  auricle  immediate^  relaxes  as  indicated  by  the  irregular 
outline  in  (J),  and  blood  runs  into  it  from  the  great  veins 
causing  a  fall  in  the  venous  curve.  At  (3)  the  ventricle 
contracts  and  forces  blood  out  into  the  aorta  as  indicated 
by. the  arrow.  Simultaneously  with  this  contraction  there 
is  an  upstroke  in  the  venous  curve  (c).  The  letter  c  was 
first  used  to  denote  carotid  pulse.  It  was  formerly  thought 
that  the  curve  c  was  due  to  the  receiver  being  held  over 
the  carotid  artery,  but  experiments  in  dogs  with  no  carotid 
artery  give  this  same  wave,  so  that  it  may  be  due  to  a 
back  wave  up  through  the  auricle  to  the  vein. 

One-tenth  of  a  second  later  the  upstroke  at  5  occurs  in  the 
radial  tracing,  this  delay  being  due  to  the  time  taken  by  the 
pulse  wave  to  travel  from  the  heart  to  the  radial  artery. 
The  reference  (4)  shows  another  stage  in  the  middle  of 
ventricular  systole.  It  will  be  noticed  here  that  during 
systole  no  blood  can  pass  from  auricle  to  ventricle,  there- 
fore the  auricle  fills  up,  and  as  it  fills  blood  gradually  backs 
up  in  the  veins  above  it  depending  upon  conditions  in 
the  general  circulation.  On  this  account  the  venous 
curve  after  the  quick  up  and  down  wave  due  to  systole 
of  the  ventricle,  will  gradually  rise  to  the  point  v.  This 
rise  may  be  small  or  if  the  veins  are  very  full  it  may  be  a 
sharped  peaked  curve.  It  is  important  to  remember  this 
as  one  is  othenvise  often  puzzled  by  the  variations  in  this 
wave. 

At  (5)  the  ventricle  relaxes  (end  of  ventricular  systole) 
as  shown  by  the  irregular  line.     As  it  does  so  the  pressure 


76  THE  HEART  RHYTHMS 

within  it  falls,  and  the  accumulated  blood  in  the  auricle 
rushes  down  into  the  empty  ventricle,  not  from  a  contrac- 
tion of  the  auricle,  but  merely  on  account  of  the  blood  there 
being  at  a  higher  pressure  than  in  the  empty  ventricle. 
This  is  accompanied  by  a  sudden  drop  in  the  venous  curve 
denoted  by  v  (ventricular  wave).  One  often  speaks  of  the 
a,  c,  and  v  waves.  At  v  we  really  have  a  drop  in  the  venous 
curve,  not  an  up  wave.  On  account  of  the  filhng  of  the 
veins  during  ventricular  contraction  the  venous  curve  may 
rise  giving  a  sharp  peak  just  before  v,  but  at  this  point  the 
curve  should  show  a  sudden  fall.  At  the  same  time  (not 
one-tenth  of  a  second  later)  the  dicrotic  notch  occurs 
in  the  radial  tracing. 

The  ventricle  and  auricle  then  both  gradually  fill,  and 
the  cycle  is  repeated. 

One  should  practice  drawing  a  complete  set  of  diagrams 
for  oneself  until  he  is  familiar  with  the  course  of  events 
in  a  cardiac  cycle  as  there  is  no  use  in  attempting  to  interpret 
polygraphic  curves  without  understanding  this  completely. 

From  a  study  of  the  above  curves  it  will  be  seen  that  we 
can  fix  four  points  with  certainty.     These  are, 

1.  Beginning  of  ventricular  systole  in  the  radial  curve 
(upstroke  S). 

2.  End  of  systole  in  the  radial  curve  (dicrotic  notch  d). 

3.  The  beginning  of  systole  may  be  plotted  onto  the  ven- 
ous curve  by  marking  a  point  one  tenth  of  a  second  earher 
in  the  venous  curve  (upstroke  c). 

4.  The  end  of  systole  may  be  plotted  on  the  venous 
curve  by  measuring  up  directly  from  the  dicrotic  notch. 
This  gives  (y)  at  the  beginning  of  the  downstroke  of  the 
wave. 


POLYGR.\PH   AND   SPHYGMOGR.\PH  77 

In  this  figure  the  pens  for  both  cun^s  are  writing  directly  over 
each  other,  as  shown  by  the  ordinates  x  and  y,  Hnes  made  by  moving 
each  pen  on  the  paper  to  record  their  relative  positions.  In  all 
curves  these  ordinates  are  necessary  and  all  measurements  are  made 
from  them.  For  example  in  this  curve  with  the  pens  directly  over 
each  other,  the  point  v  is  over  d.  If  however  the  pen  for  the  venous 
curve  were  not  directly  over  the  arterial  pen,  v  would  not  come  over 
d.  In  order  to  plot  d  onto  the  venous  curve,  its  distance  from  y 
would  be  measured,  this  distance  would  then  be  laid  off  from  x 
along  the  venous  curve  and  v  fixed.  These  ordinates  must  be  given 
with  each  tracing  or  it  is  of  no  use. 

No  other  points  can  be  fixed.  With  polygraphic  tracings 
we  axe  then  able  to  fix  the  beginning  and  end  of  systole 
in  the  radial  curve,  and  have  an  exact  method  for  determin- 
ing the  rate  and  rhythm  of  the  left  ventricle  if  all  the  beats 
are  transmitted  to  the  wrist.  In  many  cases  however 
of  weak  and  irregular  hearts  the  small  premature  beats  send 
too  small  a  pulse  wave  to  be  felt  or  recorded  at  the  wrist, 
and  one  of  the  first  things  which  must  be  done  in  polygraphic 
tracings  is  to  compare  the  radial  pulse  with  the  cardiac 
impulse  or  heart  sounds  to  determine  if  any  beats  fail  to 
reach  the  wrist. 

In  the  normal  venous  pulse  curve  there  are  three  waves 
in  each  cycle,  and  we  are  able  to  fix  two  of  these  from  plot- 
ting them  from  the  radial  curve,  namely  the  beginning  and 
end  of  systole.  The  third  wave  in  the  cycle  should  be  due 
to  contraction  of  the  auricle,  but  we  have  no  way  of  fixing 
it.  From  our  knowledge  of  heart  physiology  however  we 
have  two  points  which  help  us  to  decide  about  these  auricu- 
lar waves,  one  is  that: 

1.  Auricular  waves  occur  at  regular  intervals.  The  two 
exceptions  being  a  gradual  variation  in  rate  due  to  sinus 
arrhythmia,  or  to  a  sudden  break  in  the  rhythm  due  to  pre- 
mature ectopic  beats. 


78  THE   HEART  RHYTHMS 

2.  Auricular  waves  occur  normally  about  one-fifth  of 
a  second  before  the  carotid  waves. 

If  then  we  are  given  a  polygraphic  curve  to  interpret 
we  first  fix  the  beginning  and  end  of  systole  on  the  radial 
curve,  plot  these  points  onto  the  venous  curve  with  exact- 
ness marking  each  of  them  regardless  of  where  they  fall, 
mark  them  c,  and  v,  and  then  plot  points  one  fifth  of  a  second 
before  the  c  points  and  mark  these  with  a  ?  mark.  These 
are  the  only  possible  points  which  one  can  fix,  and  the  in- 
terpretation must  be  made  from  them. 

Next  one  should  see  if  waves  occur  at  the  points  where 
the  a  waves  are  to  be  expected.  If  they  do,  mark  them  with 
a  if  no  other  waves  are  left  unaccounted  for  one  is  then  in 
possession  of  sufficient  data  to  make  a  diagnosis.  If  how- 
ever other  waves  occur  in  the  venous  pulse  which  cannot 
be  accounted  for  by  the  fixing  of  the  above  points,  the 
only  things  which  other  waves  can  be  are  auricular  waves 
or  artefacts,  or  if  the  a  waves  occur  slightly  out  of  place, 
or  some  or  all  of  them  are  absent  the  only  way  to  make  a 
diagnosis  is  to  plot  out  just  what  we  really  have,  and  then 
see  with  which  one  of  our  known  cardiac  rhythms  this  best 
agrees.  It  is  self  evident  that  without  a  complete  knowledge 
of  all  cardiac  rhythms  it  is  useless  to  try  and  make  a  diagno- 
sis by  exclusion. 

Let  us  take  one  or  two  curves  as  examples. 

Before  taking  a  tracing  each  pen  should  be  swung  back 
and  forth  to  give  the  ordinates  x  and  y,  their  relative  posi- 
tions on  the  paper,  as  described  above.  If  they  are  so 
arranged  that  they  are  just  over  each  other,  then  the  points 
on  the  radial  curve  can  be  plotted  vertically  onto  the  venous 
curve,  if  however  they  are  not  over  each  other  as  is  usually 
the  case,  the  points  on  the  radial  curve  may  be  transferred 
to  the  venous  curve  by  taking  a  strip  of  paper  laying  it 


POLYGRAPH  .\ND   SPHYGMOGRAPH 


79 


along  the  radial  curve,  marking  the  ordinate  x  and  the 
points  5  and  d  of  each  pulse  curve.  Then  by  laying  this 
paper  on  the  venous  curve  mth  the  ordinate  x  on  the 
ordmate  y  the  points  5  and  d  may  be  marked  off  onto  the 
venous  curve  and  given  their  proper  lettering  c  and  v. 
The  c  points  will  however  all  be  moved  back  {towards  the 
ordinate)  one-tenth  of  a  second  to  allow  for  the  time  taken  for 
the  pulse  wave  to  reach  the  wrist  as  already  described. 

One  should  then  measure  the  time  intervals  as  recorded 
by  the  time  marker  and  notice  if  they  are  all  equidistant, 


Tirm  /; 


s  s  s  s  s  s 

Fig.  37.  A  normal  polygraphia  curve,  showing  the  plotting  of  the  beginning  and 
end  of  systole  onto  the  venous  curve,  the  c  and  v  points,  and  the  probable  location 
of  the  auricular  waves  at  points  one  fifth  of  a  second  before  the  c  waves.  These 
are  the  only  points  which  we  can  fix  in  the  polygraphia  curves. 

in  order  to  tell  if  the  paper  is  running  evenly.  Slight  varia- 
tions in  the  rate  of  movement  of  the  paper  often  give  very 
confusing  curves  if  this  is  not  checked  up. 

Next  we  mark  off  points  one-fifth  of  a  second  before  the 
c  points,  which  is  easily  done  as  the  time  intervals  in  most 
polygraphs  is  one-fifth  of  a  second.  These  points  are 
marked  with  a  ?  mark.  We  have  now  fixed  all  the  points 
which  we  can  and  we  are  ready  to  interpret  the  curve. 

At  the  points  c  we  should  have  an  up  wave  in  the  curve, 
due  to  the  carotid  beat,  and  at  the  points  v,  there  should  be 
a  decided  fall  in  the  curve,  for  the  reasons  described  above. 


80 


THE  HEART   RHYTHMS 


At  the  points  marked  with  the  ?  we  should  expect  to  find 
upward  curves  which  are  the  auricular  beats.  In  the  curve 
under  examination  we  find  that  all  these  factors  occur  as 
we  expect  and  that  there  are  no  other  waves  which  are  un- 
accounted for,  the  a-c  interval  or  conduction  time  is  normal 
and  we  may  then  feel  quite  certain  that  we  are  dealing  with 
a  normally  beating  heart. 


Time  'Is 


s  s 


Fig.  38.  Another  illustrative  curve  showing  the  location  of  the  c  and  v  waves 
and  the  marking  of  the  points  where  the  a  waves  should  normally  come,  one-fifth 
of  a  second  before  the  c  waves.  It  is  found  that  waves  occur  in  the  venous  tracing 
near  the  normal  points  for  the  a  waves  but  not  exactly  at  these  points.  These 
waves  are  however  equidistant  from  one  another,  and  all  but  one  are  followed  by  a 
ventricular  beat.  The  curve  would  show  a  gradual  increase  of  conduction  time 
with  a  dropped  ventricular  beat  after  the  fourth  auricular  beat  if  it  were  not  for 
the  two  waves  at  r.  It  has  already  been  found  that  all  ventricular  beats  are 
transmitted  to  the  wrist,  so  that  these  cannot  be  ventricular  beats,  they  are  out 
of  time  for  auricular  beats  and  they  are  not  followed  in  the  radial  curve  by  ven- 
tricular beats,  so  that  they  are  neither  auricular  or  ventricular  beats  and  must 
be  due  to  some  mechanical  movement  of  either  the  patient  or  the  instrument. 

If  however  we  have  a  curve  as  shown  in  figure  ?>^,  com- 
plications will  arise. 

Here  again  we  examine  the  time  marker,  measure  off 
the  points  5  and  d  on  the  radial  curve,  plot  these  from  the 
ordinates  onto  the  venous  curve,  remembering  that  the 
point  c  will  come  one  tenth  of  a  second  before  s.  Mark 
points  one  fifth  of  a  second  before  the  c  points  on  the  ven- 
ous curve  with  ?  marks,  and  then  examine  the  curve. 


POLYGRAPH  AND    SPHYGMOGRAPH  81 

In  the  first  place  we  find  that  the  ventricular  radial  beats 
are  not  regular.  We  know  that  there  are  several  causes 
of  ventricular  irregularity  but  the  one  which  it  is  important 
to  think  of  at  once  is  whether  there  is  absolute  irregularity, 
that  is  auricular  fibrillation.  If  this  condition  is  present 
there  ^\dll  be  no  auricular  waves.  Examining  the  curve 
for  auricular  waves  which  should  fall  in  a  normal  heart 
at  the  points  marked  wth  a  ?,  we  find  that  there  is  a  wave 
at  the  first  mark,  and  a  small  wave  near  each  of  the  others 
except  next  to  the  last  one  where  the  curve  is  very  irregular. 
If  one  now  starts  with  the  first  of  these  waves  which  are 
thought  to  be  auricular  waves  and  tests  their  regularity 
by  measuring  the  distance  between  them  it  will  be  found  that 
they  are  all  equidistant  and  that  there  is  one  wave  falling 
in  the  right  interval  which  is  not  followed  by  a  ventricular 
wave.  If  one  measures  the  distance  from  the  beginning 
of  each  of  these  waves  to  the  point  c  (the  a-c  distance) 
representing  conduction  time  from  auricle  to  ventricle,  it 
will  be  found  that  it  gradually  increases  up  to  the  one  which 
is  not  followed  by  a  ventricular  beat,  and  that  the  next 
auricular  wave  which  is  followed  by  a  ventricular  beat 
is  of  the  original  a-c  distance.  We  have  then  a  gradually 
increasing  a-c  distance,  or  a  lengthened  time  of  conduction, 
and  in  one  instance  a  dropped  ventricular  beat,  in  other 
words  we  are  dealing  with  a  case  of  partial  heart  block. 

We  now  examine  the  curve  and  see  if  anything  remains 
unaccounted  for,  and  we  find  a  double  curve  in  the  venous 
tracing  at  r,  which  we  have  not  yet  accounted  for.  This 
must  be  either  an  auricular  or  ventricular  beat  or  an  arte- 
fact. The  wave  at  r,  is  not  followed  or  accompanied  by 
a  ventricular  beat,  each  apex  beat  is  transmitted  to  the 
wrist,  it  does  not  come  at  the  regular  auricular  time;  it 
is  therefore  neither  a  ventricular  or  auricular  beat  but  must 


82  THE   HEART  RHYTHMS 

be  due  to  some  mechanical  disturbance  of  the  levers,  as 
coughing,  moving,  etc. 

Each  curve  must  be  worked  out  in  some  such  systematic 
way  as  this.  The  important  points  to  remember  are  to 
first  see  that  the  time  marker  is  running  evenly,  then  fix 
the  beginning  and  end  of  systole  in  both  the  radial  and 
venous  curve,  and  lay  off  the  points  where  the  auricular 
beats  should  arise;  having  done  this  next  look  for  auricular 
waves  which  should  be  equidistant  except  where  there  is 
a  gradual  variation  in  their  rate  due  to  sinus  arrhythmia, 
or  a  decided  and  abrupt  change  due  to  premature  beats. 

A  review  of  these  different  methods  of  recording  the  heart 
rhythms  shows  us  that  the  electrocardiograph  gives  us 
complete  information.  It  is  merely  necessary  to  take  a 
curve,  plot  out  the  auricular  and  ventricular  beats,  their 
time  relations  to  each  other,  and  the  points  of  origin  of  the 
impulses  and  one  will  be  able  to  locate  the  rhythm  in  its 
proper  place  in  our  classification.  With  the  polygraph  our 
information  is  always  incomplete.  We  may  be  able  to 
tell  the  time  relations  of  the  auricular  and  ventricular 
beats,  but  we  cannot  tell  the  point  of  origin  of  impulses 
directly.  For  instance  it  is  impossible  by  the  tracing  alone 
to  distinguish  between  the  ectopic-auricular  beats  of  paroxys- 
mal tachycardia,  and  the  normal  auricular  beats  of  a  rapidly 
beating  heart.  It  is  on  this  account  that  it  is  essential 
to  have  a  complete  knowledge  of  the  heart  rhythms  to 
interpret  a  polygraphic  or  sphygmographic  curve.  In 
order  to  aid  one  in  getting  a  clear  picture  of  all  these  different 
rhythms  the  following  diagrammatic  curves  of  each  type 
of  heart  rhythm  are  given.  The  polygraphic  curve  is  given 
and  below  it  the  auricular  and  ventricular  beats  plotted  out 
in  a  diagrammatic  scheme.  As  such  curves  give  also  the 
sphygmographic  tracings  one  can  use  the  same  curves  in 
discussing  this  instrument,  and  the  arterial  pulse. 


CIL\PTER  III 

POLYGRAPHIC   CURVES 
I.    SINO-AXIRICULAR  RHYTHMS 

a.  Normal  heart  heat.  This  has  been  taken  up  so  often 
before  that  it  is  unnecessary  to  repeat  the  curve,  it  is  im- 
portant to  remember  however  that  the  auricular  beats 
occur  at  regular  intervals,  that  they  are  followed  in  one- 
fifth  of  a  second  by  the  ventricular  beats,  and  that  in  plot- 
ting the  beginning  of  ventricular  systole  onto  the  venous 
curve  the  point  c  will  come  one-tenth  of  a  second  earlier 
in  the  venous  curve,  while  the  point  v  is  plotted  up  directly 
from  the  dicrotic  notch,  finally  to  remember  to  plot  all 
points  from  the  ordinates  x  and  y. 

b.  Simple  tachycardia.  Here  there  is  an  increased  auric- 
ular rate,  the  conduction  time  will  remain  normal,  the 
increase  in  rate  will  be  found  to  be  due  to  shortening  of  the 
diastoHc  interval.     The  rhythm  will  be  regular. 

c.  Simple  bradycardia.  The  slow  heart  rate  is  here  ar- 
rived at  by  a  lengthened  diastoUc  period,  but  the  conduction 
time  will  be  found  to  be  normal.     The  rhythm  is  regular. 

d.  Sinus-arrhythmia.  Here  the  rate  of  auricular  beats 
undergoes  a  gradual  variation  due  to  direct  chemical  or 
nervous  stimulation  of  the  sino-auricular  node.  The  change 
in  rate  will  always  be  found  to  occur  gradually,  no  sudden 
break  ever  occurring.  Such  a  rhythm  is  shown  in  figure 
39  and  it  is  seen  that  the  gradual  variation  in  rate  is  due  to 
changes  in  rate  of  the  auricular  beats.  The  conduction 
time  is  normal  and  the  pulse  curve  shows  a  gradual  change 
in  rate. 

83 


84 


THE  HEART  RHYTHMS 


Timz'/s. 


\     \      \        \      \     \ 


a    o 


Fig.  39.  Sinus  arrhythmia. 

c         V  ^  c         V         c^     V 


C_        V  a 


Time'/s 


Fig.  40.  Ectopic-auricular  beat.  This  occurs  prematurely  and  is  followed  by 
a  normal  auricular  beat  which  occurs  also  in  a  shorter  interval  than  normal.  The 
normal  rhythm  is  then  interrupted  by  two  beats. 


Tima'/s'- 


^      ^      ^   ^         ^      "^ 

Fig.  41.  This  is  another  curve  of  a  premature  ectopic-auricular  beat  which  is 
followed  by  the  normal  auricular  beat  in  such  a  time  that  the  regular  rhythm  is 
broken  only  by  the  one  premature  beat. 


Time,'/^'. 


\    \    SIS    s^ 

Fig.  42.  Curve  of  an  ectopic  auricular- ventricular  nodal  beat,  which  occurs 
prematurely  and  is  followed  in  such  time  by  the  normal  auricular  beat  that  the 
normal  rhythm  is  interrupted  by  two  beats. 


POLYGR.\PHIC   CUR\^ES  85 

n.   ECTOPIC   BEATS    INTERRUPTING    NORMAL    RHYTHMS 

a.  Ectopic-aiiricidar  beats.  In  all  of  these  ectopic  beats 
we  have  a  normal  regular  rhythm  interrupted  by  single  or 
multiple  beats  of  ectopic  origin.  It  will  be  noticed  that 
there  are  never  any  extra  beats  but  that  a  beat  occurs 
prematurely.     Such  a  beat  is  shown  in  figure  40  and  42. 

The  normal  point  of  origin  of  impulses  is  the  sino-auricular 
node  the  auricle  beating  first  and  the  ventricle  following  it, 
we  therefore  always  look  at  the  auricular  heat  first,  and  work 
out  the  rhythm  from  it.  Here  we  see  that  we  have  a  regu- 
larly beating  auricle  interrupted  at  L  by  an  auricular 
beat  coming  prematurely,  this  is  followed  in  a  shorter  time 
than  the  regular  auricular  rhythm  by  another  auricular 
beat  and  then  the  regular  auricular  rhythm  is  again 
established  at  the  original  rate. 

Each  auricular  beat  is  followed  in  the  normal  time  by 
a  ventricular  beat  so  that  the  radial  curve  shows  the  same 
irregularity  as  the  auricular  rhythm.  Two  heats  are  out 
of  time.  This  is  due  to  the  premature  beat  and  to  the  normal 
auricular  beat  following,  occurring  also  prematurely.  All 
of  this  is  easily  seen  in  the  polygraphic  curve  but  it  is  im- 
portant to  compare  the  two  radial  beats  which  are  out  of 
time  with  the  one  beat  which  we  will  find  out  of  time  in  the 
radial  tracing,  when  we  have  an  ectopic  beat  of  other  origin. 

In  figure  41,  however  a  curve  is  given  in  which  we  have 
an  ectopic-auricular  beat  the  same  as  in  the  above  curve, 
in  which  the  auricular  beat  following  the  premature  one 
comes  in  the  normal  auricular  interval.  In  this  case  only 
one  auricular  and  one  ventricular  beat  is  out  of  time  and 
it  cannot  be  distinguished  from  the  ectopic  beats  of  other 
origin. 

b.  Ectopic  auricular-ventricular  nodal  heats.  An  ectopic 
beat    of    auricular-ventricular    nodal    origin    is    shown    in 


86 


THE   HEART  EHYTHMS 


figure  42.  Here  the  regular  rhythm  is  interrupted  by  a 
premature  beat  arising  from  the  auricular-ventricular 
node.  Both  the  auricle  and  ventricle  beat  at  once.  This 
is  shown  by  the  abnormally  large  venous  wave  occurring 
at  the  time  of  ventricular  contraction  while  the  radial 
pulse  wave  is  if  anything  smaller  than  normal.  The  next 
auricular  beat  from  the  sino-auricular  node  may  occur 
as  in  the  case  of  the  ectopic-auricular  beat,  either  slightly 
earlier  than  normal  or  in  the  normal  time,  in  which  case  there 
may  be  either  one  or  two  beats  out  of  time  in  the  radial 
curve. 


Tirm'/s 


\      \      \    .'        \      \ 

Fig.  43.  Ectopic-ventricular  beat.  Here  the  rhythm  is  interrupted  by  the 
premature  ectopic-ventricular  beat  only.  The  next  auricular  beat  falls  in  the 
refractory  period  of  the  ventricle  and  this  fails  to  respond  but  does  so  to  the  next 
auricular  beat. 

c.  Ectopic-ventricular  heats.  In  this  condition  there  is 
no  abnormality  of  the  sino-auricular  node  therefore  we 
will  find  a  regularly  beating  auricle.  Each  auricular  beat 
will  be  followed  by  a  ventricular  beat  in  the  normal  time 
until  we  have  one  ventricular  beat  occurring  prematurely 
as  shown  in  figure  43.  When  the  next  auricular  impulse 
comes  to  the  ventricle  it  finds  it  in  the  refractory  state  and 
it  cannot  contract,  so  that  this  auricular  beat  will  not 
be  followed  by  a  ventricular  beat,  but  the  next  auricular 
impulse  finds  the  ventricle  again  ready  for  contraction, 
and  it  is  followed  by  a  ventricular  beat.    We  have  then 


POLYGRAPHIC   CURVES  87 

only  one  interruption  to  the  normal  rhythm,  and  that  is 
the  single  premature  ventricular  beat. 

This  rather  lengthy  description  is  given  to  enable  one 
to  differentiate  by  means  of  the  sphygmograph  alone  an 
ectopic-auricular  from  an  ectopic-ventricular  beat.  It  will 
however  be  seen  that  the  auricular  and  auricular-ventricular 
nodal  beats  may  both  give  a  single  interruption  to  the 
regular  rhythm  which  is  exactly  similar  to  the  interruption 
caused  by  a  premature  ventricular  beat.  The  only  diagnos- 
tic point  of  any  value  is  then,  that  if  the  regular  rhythm  is 
interrupted  by  two  beats  in  succession  the  ectopic  beat  is 
not  of  ventricular  origin  but  of  either  ectopic-auricular 
or  auricular-ventricular  nodal  origin.  The  origin  of  any 
ectopic  beat  may  however  be  determined  by  the  use  of  the 
electrocardiograph . 

III.    ECTOPIC-AURICULAR   RHYTHMS 

a.  Paroxysmal  tachycardia.  Here  we  have  a  very  fast 
regular  rhythm  of  ectopic  origin,  all  of  the  auricular  beats 
arising  from  an  ectopic  focus  in  the  auricle.  They  are 
followed  in  the  normal  or  slightly  reduced  conduction  time 
by  normal  ventricular  beats.  The  polygraphic  curves  can 
in  no  way  be  distinguished  from  a  fast  beating  normal  heart, 
as  the  auricular  beats  arise  at  regular  intervals,  and  each  is 
followed  by  a  ventricular  beat.  Such  a  curve  is  shown  in 
figure  44. 

h.  Auricular  flutter.  In  this  condition  the  auricle  is 
contracting  at  regular  intervals  and  at  such  a  fast  rate  that 
it  is  impossible  for  the  ventricle  to  follow  it.  Two  conditions 
may  then  result  as  shown  in  figures  45  and  46.  In  the  first 
the  ventricle  may  follow  a  regular  number  of  auricular 
beats  giving  a  regular  pulse  which  may  be  of  fairly  normal 


THE  HEAUT  RHYTHMS 


vOl'c      Ov  at  c      ^•'    r      "a   '^/N''/V<^/\'k  'j 


Timers'. 


Fig.  44.  Curve  of  paroxysmal  tachycardia  which  will  be  seen  to  be  indis- 
tinguishable from  a  rapid  normal  rhythm. 


Timz'/s" 


V  V '  S"  S"  V  V'V  " 

Fig.  45.  Curve  of  auricular  flutter.     The  ventricle  follows  a  regular  number  of 
auricular  beats  and  gives  a  regular  slow  ventricular  pulse. 


Tone.  'Is 


Fig.  46.  Auricular  flutter  in  which  the  ventricle  follows  an  irregular  number  of 
auricular  beats  and  is  very  irregular. 


Tiim'js 


III  \  %  I 

Fig.  47.  Curve  of  auricular  fibrillation  in  which  no  auricular  waves  are  seen, 
and  the  ventricle  beats  absolutely  irregularly. 


POLYGRAPHIC    CURVES  89 

rate.  In  the  second  condition  the  ventricle  follows  an 
irregular  number  of  auricular  beats  and  will  then  show  all 
manners  of  irregularity.  Sometimes  pulses  can  be  made 
out  in  which  the  ventricular  beats  occur  in  groups  following 
first  three,  then  four  auricular  beats.  If  such  regular 
groupings  occur  in  the  radial  pulse  one  feels  that  there  must 
be  a  controlling  factor;  that  there  must  be  a  beating  auricle, 
and  that  the  ventricular  rhythm  must  be  due  either  to  a 
condition  of  auricular  flutter,  or  to  heart  block,  which  will 
be  taken  up  later,  the  principle  being  the  same  however, 
the  ventricle  following  first  one  number  and  then  another 
of  auricular  beats.  In  flutter  this  irregular  beat  of  the 
ventricle  is  due  to  its  being  unable  to  maintain  the  auricular 
rate,  while  in  the  case  of  heart  block  the  conduction  is  so 
poor  that  all  auricular  impulses  do  not  reach  the  ventricle. 

c.  Auricular  fibrillation.  In  this  condition  there  is  no 
coordinate  contraction  of  the  auricle,  no  auricular  waves 
can  therefore  be  made  out.  The  venous  curve  will  show 
simply  c  and  v  waves  due  to  the  beginning  and  end  of  ventric- 
ular systole.  As  there  is  no  regular  auricular  rhythm  but  a 
very  irregular  auricular  impulse  formation  the  ventricle 
will  respond  to  only  those  irregular  impulses  which  reach 
it  and  its  rhythm  will  be  one  of  absolute  irregularity.  Such 
a  curve  is  shown  in  figure  47. 

IV.    AimiCULAR-VENTRICULAR   NODAL  RHYTHM 

This  is  an  exceedingly  rare  condition.  The  impulse 
for  contraction  arises  at  the  auricular-ventricular  node 
and  is  transmitted  to  the  auricle  and  ventricle  in  the 
same  length  of  time  so  that  the  auricle  and  ventricle 
beat  simultaneously.  In  such  a  case  the  a  and  c  waves 
would  occur  at  the  same  time  and  make  one  wave,  no 
separate  a  waves  would   appear,    and   the  venous  curve 


90 


THE   HEART   RHYTHMS 


would  consist  only  of  the  combined  a  and  c  wave  and 
the  V  wave.  The  rhythm  would  be  regular  as  all  un- 
interrupted rhythms  are,  and  therefore  we  would  have 
a  regular  arterial  pulse.  The  simultaneous  beat  of  the 
auricle  and  ventricle  give  an  abnormally  high  and 
sharp  wave  occurring  at  the  beginning  of  ventricular 
systole,  while  the  arterial  pulse  wave  is  of  the  normal  size 
as  shown  in  figure  48.  The  diagnosis  of  this  condition  has 
to  be  made  with  caution,  if  the  polygraph  alone  is  used. 
It  is  based  on  having  a  regular  rhythm,  no  auricular  com- 


Tiim'/s 


!    !    1    I    :    I 

Fig.  48.  Curve  of  auricular- ventricular  nodal  rhythm,  in  which  the  ventricle 
bdats  regularly  and  gives  an  abnormally  high  c  wave  in  the  venous  curve.  No 
auricular  waves  are  visible.  Car<^  should  be  taken  in  making  a  diagnosis  of  auric- 
ular-ventricular nodal  rhythm  from  such  a  curve  alone,  as  a  very  similar 
curve  may  be  obtained  by  placing  the  venous  receiver  over  the  carotid  ar^^ery  and 
missing  the  venous  curve  altogether  in  a  normally  beating  heart. 

plexes,  and  an  unusually  high  c  wave.  But  one  can  see 
that  it  is  perfectly  possible  to  place  the  venous  receiver  on 
the  neck  in  such  a  way  that  one  will  be  able  to  record  carotid 
beats  and  not  record  the  venous  pulse  at  all,  in  which  case 
of  course  no  auricular  beats  could  be  seen.  The  condition 
is  so  rare  that  one  mil  hardly  ever  see  it,  and  most  all  cases 
in  which  a  regular  ventricular  venous  pulse  is  found  with 
no  signs  of  auricular  waves,  will  be  found,  if  an  electrocardio- 
gram is  taken,  to  be  due  to  the  manner  in  which  the  venous 
curve  was  taken.     In  fact  in  the  hands  of  the  beginner 


POLYGRAPHIC  CURVES  91 

more  than  half  of  the  tracings  taken  will  be  found  to  con- 
sist of  nothing  but  the  carotid  pulse  instead  of  the  venous 
curve. 

V.   ECTOPIC-VENTRICULAR  RHYTHMS 

We  haA'e  seen  that  if  runs  of  ectopic  beats  arise  in  the 
ventricle  they  must  be  rapid  or  the  auricle  breaks  in  and  the 
normal  rhythm  is  set  up  again.  On  the  other  hand  if 
the  run  of  ectopic  beats  is  rapid  and  prolonged  the  circula- 
tion fails  and  the  patient  becomes  unconscious  and  dies. 
There  is  then  a  very  narrow  limit  of  rates  within  which  it 
is  possible  to  have  ventricular  rhythms  compatible  mth 
life,  and  we  may  from  a  practical  point  of  view  consider 
that  they  do  not  occur.  They  are  theoretically  possible 
however. 

VI.   ABNORMALITIES  OF  CONDUCTION  FROM  AURICLE 
TO    VENTRICLE 

a.  Prolonged  conduction  time.  In  certain  conditions  of 
toxic  poisoning,  or  pressure,  the  conduction  from  auricle 
to  ventricle  is  impaired  and  it  takes  the  impulse  more  than 
the  customary  one-fifth  of  a  second  to  pass  from  auricle 
to  ventricle.  If  this  lengthened  conduction  time  is  not  too 
great  the  ventricle  will  still  follow  each  auricular  beat, 
and  the  curve  will  show  no  changes  from  the  normal  except 
an  increased  a-c  interval.  Such  a  curve  is  given  in  figure 
49.  The  arterial  pulse  will  be  perfectly  regular  and  no 
abnormahty  can  be  made  out  without  the  ^•enous  tracing 
being  taken. 

b.  Dropped  heats  or  partial  block.  If  the  impairment  of 
conduction  increases  so  that  all  auricular  impulses  are  not 
transmitted  to  the  ventricle  it  will  be  found  that  every 
once  in  awhile  one  ventricular  impulse  will  be  dropped,  as 
shown  in  figure  50. 


92  THE  HEART   RHYTHMS 

Polygraphic  tracings  give  us  complete  information  in  such 
cases  as  the  auricular  and  ventricular  waves  are  both  shown, 
and  the  conduction  time  may  be  measured.  The  arterial 
pulse  may  however  be  very  deceptive.  The  gradual  in- 
crease in  conduction  time  makes  a  slight  lengthening  of 
time  between  the  arterial  beats,  and  an  interval  where  the 
beat  is  dropped.     Single  beats  are  easily  recognized  by 


Time'/s 


■^    ^    ^    -^    ■-.    ^ 

Fig.  49.  This  shows  a  simple  prolongation  of  the  conduction  time  but  each 
auricular  beat  being  followed  by  a  ventricular  beat. 


Timers' 


Fig.  50.  In  this  curve  the  conduction  time  is  prolonged  after  each  of  the  first 
three  beats  until  the  fourth,  where  the  auricular  impulse  does  not  reach  the  ventricle 
and  one  ventricular  beat  is  dropped.  The  next  auricular  beat  passes  to  the  ventricle 
and  the  cycle  is  repeated. 

these  factors.  Where  beats  are  dropped  at  regular  or 
recurrent  intervals  the  condition  may  be  made  out  from 
the  radial  pulse  alone.  For  instance  if  each  fourth  beat 
is  dropped,  one  will  find  a  gradual  lengthening  of  the  in- 
terval between  beats,  and  then  a  dropped  beat,  the  sequence 
of  events  being  repeated  regularly.  Or  one  may  find  a 
gradual  increasing  distance  between  the  radial  beats,  and 
then  a  dropped  beat  occurring  after  first  three  and  then  four 


POLYGR.\PHIC   CUE.\TS  93 

auricular  beats  alternately.  But  when  the  ventricle  follows 
no  regular  number  of  auricular  beats,  the  pulse  curve  loses 
all  signs  of  regularity  and  the  condition  cannot  be  told  by 
the  arterial  pulse  alone  from  the  absolute  irregularit\'  of 
auricular  fibrillation  or  of  multiple  ectopic  beats. 

c.  Complete  block.  Finally  we  have  a  condition  of  com- 
plete block,  which  has  been  described  above  in  which  no 
auricular  beat  can  reach  the  ventricle  and  the  ventricle 
takes  on  a  rhythm  of  its  own,  known  as  an  idio-ventricular 
rhythm.  This  rhythm  is  characteristic,  as  no  other  con- 
dition (except  in  cases  of  poisoning)  gives  such  a  slow  ven- 


FiG.  51.  This  curve  shows  a  condition  of  complete  block  in  which  the  auricle 
and  ventricle  beat  absolutely  independently  of  each  other.  The  ventricular  rate 
is  characteristic  of  this  condition  being  a  little  over  twenty  per  minute. 

tricular  rate.  It  is  usually  between  twenty-four  and  thirty 
beats  per  minute,  but  may  be  higher.  A  curve  of  such  a 
condition  is  shown  in  figure  51.  Auricular  waves  are  shown 
occurring  at  regular  intervals,  and  bearing  no  relation  to 
the  ventricular  beats  which  occur  at  long  and  perfectly 
regular  intervals. 

SUMMARY   OF    POLYGRAPHIC   RHYTHMS 

If  we  summarize  this  review  of  the  polygraphic  tracings 
we  find  that  it  is  possible  to  make  the  following  diagnoses 
with  this  instrument. 

Sino-auricular  rhythms.  Complete  information  can  be 
obtained  of  all  these  rhythms  but  a  simple  tachycardia 


94  THE   HEART   EHYTHIIS 

cannot  be  distinguislied  from  parox}'smal  tachycardia  by 
the  tracing  alone. 

Ectopic  beats.  These  may  all  be  recognized,  and  the  origin 
of  the  ectopic  beat  located,  that  is  whether  it  is  auricular, 
auricular-ventricular  nodal,  or  ventricular. 

Auricular-veniricuJar  nodal  rhythms.  These  cannot  be 
proven  to  occur  as  the  diagnosis  is  based  on  the  absence 
of  auricular  waves,  and  abnormally  large  c  waves,  both  of 
which  factors  may  be  obtained  in  a  poorly  taken  normal 
rhythm  in  which  the  venous  receiver  is  placed  over  the 
carotid  arter}*  and  no  v'enous  pulse  is  recorded.  The  con- 
dition is  extremely  rare. 

ECTOPIC-AI"MCrL-\R   RHYTHMS 

Paroxysmal  tachycardia.  This  caimot  be  differentiated 
from  simple  tachycardia  by  this  instnmient  alone. 

Auricular  flutter.  This  may  give  ver\-  beautiful  auricular 
waves,  and  an  even  better  picture  than  the  electrocardio- 
gram. Sometimes  however  the  waves  are  ver}-  hard  to 
obtain. 

Auricular  fhrilhtion.  In  this  condition  no  auricular 
waves  occur  and  the  ventricle  beats  with  absolute  irregular- 
itv'.  One  is  never  certain  that  the  absence  of  auricular 
waA'es  in  the  curve  is  not  due  to  the  technique  of  taking  the 
tracing.  The  other  two  possibilities  are  multiple  ectopic 
beats,  and  irregular  heart  block.  These  of  course  would 
be  shown  m  the  venous  curv'e  if  one  were  sure  that  the 
venous  curve  were  being  taken,  but  it  is  surprising  in 
how  many  cases  the  begumer  is  unable  to  obtain  anvthing 
but  a  carotid  tracing  instead  of  the  venous  curve. 

HEART  BLOCK 

-\11  Stages  of  heart  block  may  be  shown  perfectly  by  poly- 
graphic  tracings. 


POLYGRAPHIC   CURVES  95 

SUMMARY  OF   SPHYG  MO  GRAPHIC  TRACINGS 

Sphygmographic  tracings  give  us  graphically  the  same 
information  which  we  can  obtain  by  feeling  the  pulse.  Our 
information  is  very  limited,  and  unless  it  is  combined  with 
other  clinical  signs  and  s>Tnptoms  is  of  limited  use,  but 
with  a  good  knowledge  of  the  heart  rhythms,  and  a  clear 
picture  of  the  clinical  conditions  associated  with  each, 
which  one  can  obtain  by  experience  only,  the  pulse  will 
be  found  to  be  of  great  diagnostic  aid.  It  gives  of  course 
only  ventricular  beats. 

All  regular  rhythms  cannot  be  differentiated  except  by  their 
rate.  Such  rhythms  are  the  normal  beat,  simple  tachycardia, 
simple  bradycardia,  paroxysmal  tachycardia,  auricular 
flutter,  in  which  the  ventricle  follows  a  regular  number 
of  auricular  beats,  auricular-ventricular  nodal  rhythm, 
and  heart  block  in  which  the  ventricle  follows  a  regular 
number  of  auricular  beats. 

Sinus  arrhythmia  may  be  easily  recognized  by  the  gradual 
variation  in  distance  between  the  individual  beats. 

Ectopic  heats  if  occurring  singly  may  be  recognized  as 
such.  The  normal  rhythm  is  interrupted  by  one  beat  oc- 
curring prematurely,  and  sometimes  a  second  one,  the  only 
break  in  the  regular  rhythm  any  of  the  three  t>T)cs  of 
ectopic  beats,  namely  ectopic-auricular,  auricular-ventricu- 
lar nodal,  or  ectopic-ventricular,  may  give  the  same  picture. 
If  howe\^er  the  premature  beat  is  followed  by  a  second 
beat  at  an  interval  shorter  than  the  normal  period,  and  the 
regular  rhythm  then  restored,  we  know  that  the  ectopic 
beat  is  not  of  ventricular  origin.  It  may  be  an  ectopic- 
auricular  or  an  auricular-ventricular  nodal  beat,  but  the 
two  cannot  be  differentiated. 


96 


THE   HEART  RHYTHMS 


Absolute  arrhythmia  is  always  associated  with  fibrilla- 
tion but  it  may  occur  in  multiple  ectopic  beats,  or  irregular 
heart  block. 

Periods  of  regular  beats  may  occur  in  partial  heart  block, 
but  also  in  runs  of  ectopic  beats. 

CONSTRUCTION   OF   DIAGRAMMATIC    CURVES 

In  conclusion  a  method  of  construction  of  these  dia- 
grammatic curves  is  given  as  a  help  to  those  who  wish  to 
plot  out  the  rhythms  for  themselves.  Such  a  scheme  is 
given  in  figure  52. 


Fig.  52.  Diagrammatic  method  of  constructing  polygraphic  curves  which  will 
be  found  described  in  the  text. 

One  saves  a  great  deal  of  time  by  using  a  drawing  board 
and  T-square.  First  the  nine  parallel  construction  lines 
are  ruled  off  in  pencil.  The  first  one  for  the  plotting  of  the 
venous  curve,  the  second  for  the  top  of  the  arterial  pulse 
curve,  the  third  for  the  dicrotic  notch  in  this  curve,  the 
fourth  as  a  base  line  for  the  same  curve,  the  fifth  for  the 
time  marker,  the  sixth  and  seventh  for  the  top  and  bottom 
of  the  auricular  diagram,  and  the  eighth  and  ninth  for  the 
top  and  bottom  for  the  ventricular  diagram. 

Time  intervals  are  laid  off  along  the  time  marker  fine 
at  regular  intervals.     One-half  inch  for  each  fifth  of  a  second 


POLYGRAPHIC  CURVES  97 

will  give  a  convenient  working  scale.  One  can  calculate 
quickly  the  intervals  at  which  to  put  the  auricular  beats  for 
any  given  rate  by  deciding  how  many  to  put  in  a  three 
second  interval,  this  number  multiplied  by  twenty  wall 
give  the  rate  per  minute.  For  instance  three,  a  rate  of 
sixty,  four,  one  of  eighty,  etc.  Having  decided  on  the  rate, 
let  us  suppose  the  auricular  beats  will  fall  at  two-inch  in- 
tervals. The  ruler  is  then  laid  along  the  venous  line 
(1),  and  marks  made  at  two-inch  intervals  and  marked 
(a).  One-fifth  of  a  second  after  each  of  these  will  come 
the  ventricular  waves  which  should  be  marked  by  points, 
in  this  case  one-half  inch  after  the  (a)  points.  The  duration 
of  ventricular  systole  is  a  little  more  than  the  conduction 
time  or  the  a-c  interval,  and  so  points  are  made,  let  us  say 
three-quarters  of  an  inch  after  the  c  points  and  lettered  v 
marking  the  end  of  systole.  We  now  have  all  the  beats 
plotted  out.  Construction  lines  are  now  drawn  down  from 
each  of  these  points  across  all  the  horizontal  lines.  Points 
one-tenth  of  a  second  after  each  c  line  are  marked  on  the 
base  line  of  the  radial  pulse  curve.  The  ventricular  beats 
are  now  drawn  in,  starting  each  upstroke  at  these  points, 
and  putting  in  the  dicrotic  notch  at  the  proper  place, 
shown  by  the  construction  line  from  "?;. "  The  venous 
curve  can  then  be  drawn  making  upstrokes  at  the  a,  and 
c  points,  and  down  strokes  at  the  v  points.  Finally  the 
diagrammatic  lines  for  the  auricular  and  ventricular  beats 
may  be  drawn  in. 

From  such  a  construction  it  will  be  seen  that  the  venous 
curve  gives  us  the  true  relation  of  the  beats  to  each  other. 
That  all  our  rhythms  are  based  on  the  auricular  beats, 
the  normal  controlling  pacemaker  of  the  heart,  and  the  time 
relations  of  ventricular  beats  to  these  auricular  beats  plotted. 
The  method  which  we  must  adopt  in  reading  a  tracing  is 


98  THE   HEART   KEIYTHMS 

however  the  reverse,  on  account  of  the  absence  of  charac- 
teristic venous  curves.  In  a  tracing  we  must  first  start 
with  the  ventricular  beat  as  shown  in  the  arterial  curve, 
because  it  gives  us  our  only  two  fixed  points,  the  beginning 
and  end  of  systole,  and  from  these  plot  backwards  so  to 
speak  onto  the  venous  curve  in  order  to  distinguish  there, 
auricular  from  ventricular  waves. 


INDEX 


Arrythmia,  sinus,  37. 
Auricular  beats : 

premature,  37,  85. 

ectopic,  85,  94. 
Auricular: 

complex,  30. 

fibriUation,  45,  89,  94. 

flutter,  43,  87,  94. 

"a"  waves,  17,  74. 
Auricular  ventricular. 

bundle,  29,  node  33. 

nodal  beats,  39,  85. 

nodal  rhythm,  48,  89,  94. 

Beats: 

dropped,  52,  91. 

ectopic  auricular,  37. 

ectopic   auricular  ventricular 
39,  85. 

ectopic  ventricular,  40. 

premature,  38. 
Block: 

partial,  52,  91,  94. 

complete,  52,  93. 
Bradycardia,  simple,  36. 
Bundle: 

auricular  ventricular,  29. 

of  His,  29. 

"c"  wave,  16,  74. 
Carotid  wave,  16,  74. 
"Circus"    movements,  47. 
Complex,  20. 

auricular,  30. 

ventricular,  30. 
Conduction,  27,  52. 

time,  28,  52. 
Curves: 

construction  of,  62,  96. 

examination  of,  61. 

polygraphic,  16,  64,  83. 

sphygmographic,  14,  95. 


nodal. 


Dropped  beats,  52,  91. 
Dicrotic  notch,  69. 

Ectopic  beats: 

auricular,  37,  40,  85. 

auricular  ventricular  nodal,  39,  85. 

ventricular,  40,  86. 
Ectopic  rhythms: 

auricular,  41,  87,  94. 

auricular  ventricular  nodal,  48, 89, 94. 

ventricular,  49,  91. 
Electrocardiogram,  normal,  20,  31. 

interpretation  of,  59. 
Electrocardiograph,  19. 
"Extra  Systole,"  38. 

Fibrillation. 

auricular,  45,  89,  94. 

ventricular,  49. 
Flutter,  auricular,  43,  87,  94. 

Heart  beat: 

normal,  36. 

polygraphic  curve  of,  17,  74. 
Heart  block: 

complete,  52. 

partial,  52. 
His,  bundle  of,  29. 

Idio-ventricular  rhythm,  52. 

Leads,  60. 

Node: 
■     auricular  ventricular,  33. 

sino-auricular,  32. 
Nodal  beats,  auricular  ventricular,  39. 
Normal : 

electrocardiogram,  20. 

heart  beat,  36. 

rhythm,  36. 


99 


100 


INDEX 


Orclinates,  77. 

Paroxysmal  tachycardia,  42,  87,  94. 
Period,  refractory,  27. 
Premature: 

auricular  beats,  37,  85. 

auricular    ventricular    nodal    beats, 
39,  85. 

beats,  38,  94. 

ventricular  beats,  40,  86. 
Polygraph,  16,  65. 
Polygraphia  curves,  83. 

inteipretation  of,  78. 
Pulse,  the,  13. 

radial,  13,  16,  69. 

venous,  17,  73,  74. 
"P"  wave,  20. 

"QRS"wave,  20. 

Radial  pulse,  13,  14,  69. 
Refractory  period,  27. 
Rhythms : 

auricular  ventricular  nodal,  48,  89, 

94. 
ectopic  auricular,  41,  87,  94. 
ectopic  ventricular,  49,  87,  91. 

normal,  35. 
sino-auricular,  35,  93. 

Simple  bradycardia,  36. 
Simple  tachycardia,  36. 
Sinus  arrhythmia,  37,  83. 


Sino-auricular  node,  32. 
Sino-auricular  rhythm,  35,  93. 
Sphygmograph,  14. 
Sphygmographic  curves,  95. 
String,  20. 
Systole,  "extra"  38. 

"T"  wave,  20. 
Tachycardia: 

simple,  36. 

polygraphia  curve  of,  83. 

paroxysmal,  42,  87,  94. 

"V"  wave,  17,  74. 
Venous  pulse,  17,  73. 
Ventricular  beats: 

premature  or  ectopic,  40,  86. 
Ventricular: 

beats,  premature  or  ectopic,  40, 

complex,  30. 

fibrillation,  49. 

rhythm,  ectopic,  49. 

idio-ventricular,  52. 

wave,  74. 

Waves : 

auricular,  17,  74. 
carotid,  16,  74. 
"P,"20. 
"QRS,"20. 
"T,"20. 
"v,"  17,  74. 


DUE  DATE 

201-6503 

Printed 
in  USA 

J. 


COLUMBIA  UNIVERSITY  LIBRARIES 


0037552147 


